TIPS ON PRECISION SPINDLE REBUILD

well everyone welcome to my shop I'm Robin yes I'm still alive just been really busy this video is going to be on a spindle rebuild of my track mill but I'm covering a lot of spindle rebuild and design topics through this whole thing long video you can leave comments if you think long as bad or long it's good my I'm not a spindle expert I've designed multiple hundreds of spindles and built multiple thousands of spindles personally and so I have a lot of experience but that doesn't make me an expert they started using the fastener engineering catalog back when mr. Jenkins said hey can you design spindle and I said sure so studied up on that catalog and that catalog was just a wealth of information the catalog I use for the bearing arrangement picture was courtesy of the Timken fastener engineering catalog which I will leave a link in in the notes if you download that PDF study the engineering section go to the angular contact bearings which are most common section study everything's in there digest everything that's in there look at all the different design examples of different styles of spindles what the spindles are designed for high speed spindles mill spindles laying spindles grinders bundles there's all different nuances on what's what's involved there you can know a whole lot about spindles when you get done with that so anytime anybody says hey you know where can I learn about spindles that's where I send them that's the entirety of my spindle design education was that that book so this particular video is going to cover a lot of details in there a lot of nuances many may say oh this is ridiculous you can't make any money you know building spindles like this rebuilding spindles I'm showing you best practices the spindle Reed build people the professionals would say hey the guys doing you know everything right that he could other than being in a cleanroom pretty much there might be some comments otherwise but in general I'm showing you really best practices about cleanliness and sequence of events and things a big thank you to all my subscribers thank you for your kind and gracious comments they're really appreciated it's nice to know that the the content you put out is it is useful and appreciated thank you also to my patreon supporters and PayPal supporters I only put those links in there because people who asked repeatedly how can we send something your way and that's appreciated it's not expected or required so that's the only reason it's in there enough babble let's get to it angular contact spindle bearings let's take a look at some of the details about these this is a particular number for a spindle bearing but the important part here is the D U M D is for duplex Universal means any orientation M is medium preload this NB u15 is a relatively popular high-performance grease from Kluber 25% fill that's how much of the internal volume of the bearing is filled with grease don't want much more than that because you can generate heat from being over lubricated now let's take a look at the arrangement most spindle bearings are going to be in a DB arrangement what does that mean as you can see here it says the stamped faces of the outer rings are touching each other and the contact angle is like this converging on the outside the inner races when you put these two together will have a gap here that gap has been precisely ground end to achieve a given amount of force to push these together or in other words to align this face with this face or get flush on this face all the same thing it takes a certain amount of axial force in pounds or Newtons and that is the specified amount for a particular BRE load for so for this bearing of this size there is a general poundage range that is what is considered media preload and that is exactly what it'll take to force this down to this level well how do they get that well they grind the faces they grind this face and they grind this face after the bearing has been ground the races have been ground they tune these faces to get that amount of preload and that preload also can be a considered stick out this value from here to here with just gravitational loading this way would be called the stick out amount for that size bearing for that given preload here we are shown in the loaded condition where the unit races have been clamped locking out here is providing the force to bring these till they touch and that pre loads the bearing meaning these are forcibly compressed the balls are compressed some of the races or compressed some and there's absolutely no play and the higher the preload the stiffer the bearing gets but also the RPM reading that it can go starts to diminish so very high speed bearings will have lighter pre loads or even spring preload and very slow speed heavy load spindles will have high preloads to make them stiffer you can also have a spacer in here and space these bearings apart as long as the spacers are the exactly the same length then you're not affecting the preload at all so you can get a wider stance on these bearings as will be the case with the spindle bearings that we're replacing there's tubular spacers ID and OD that are match ground and that maintains the same preload regardless of the spacing between them this particular bearing style which is typical of a general spindle bearing it's called a relieved outer race bearing why because this you see here this outer race here has been relieved there's almost no groove left on this side just enough really to hold the balls in and they actually snap in if you put too much load on these disassembling them you can actually snap these off it'll climb over the lip and come off and the balls could fall out and you've got trouble so this is a good way to identify what style it is you'll also notice on the inner race there's no difference in height the race on the inner race so this is considered a relieved outer race bearing and that helps you when you go to look at the real bearing itself and see what what your what you've got this is this is one size of bearing this is looking at it from the other side here you can see the relief face see how this is thinner right here the wall thickness is thinner this is also called the marked face these are the faces that touch the two marked faces go against each other in order to get the preload if you don't have them against each other you're going to end up with a tandem set that needs something else on the other side another set to preload it so you have to pay very close attention to which way these bearings are facing so that you do end up with the correct situation I don't know if you'll be able to see it on here or not but the there we go you'll see here there's a grind pattern on this face and this is from them removing the prescribed amount of material after testing to establish the proper stick out of the bearing on this inner race if we come over to the other side on the on the side here we will see that's oil film here the devil you see what you say there you go uh it might better there we go here you can see the lay of the grind this is ready ground the outer race lip when these are flush ground they are exactly the same width the bearings I D in a recent outer race are exactly the same width and that's considered a universal grind because that will allow you to stack them in any combination DB back to back the F face to face tandem whatever usually bearings will have a dot burnished marked whatever some kind of marking a chevron on the outside edge and lasered in whatever that - I'll show you where the eccentricity point of the races in is on each on the outer race and the inner race and when you assemble the bearings those should be aligned with each other so the dots on the outer races should align the dots on the inner races should align if you're doing real precise work those eccentricity marks all shows should be set opposite the eccentricities of the shaft are working on so that they tend to cancel each other but that's that's getting into higher end stuff that typically you don't have to worry about these particular bearings because they are a certain size they don't actually have the eccentricity marks but there is such a high level that yes they have eccentricity but it's a trivial amount for what we're doing now that we understand the situation here with the preload a it will be clear why when you tighten the whole assembly together on the mill spindle that the outer race spacer will be very difficult to move it's because it is keeping these two apart and whatever the preload was in pounds that's how much force is pressing against that spacer hole at the outer race spacer when it's tightened up so it's important to get the outer race spacer generally in line before you Snug the nut completely otherwise you're going to tap it around to get it so that it'll slide back into the spindle housing there's some screw that snugs the lock ring in place and we're taking that completely out when you put this back in be very careful not to over tighten this this just needs to touch the ring snug enough that it wouldn't spin free for vibration any tighter than that and you deform the out the tubular shape of the quill and we'll make it bind as it goes up into the into the housing here I always use precision ground stones after I've snugged it to stone over this in case there's any burrs for mall so you're probably like me and don't have a spanner wrench laying around so here's a trick that will allow you to get spanner rings like this off without without causing a lot of damage just put a six millimeter dowel actually if I if I had a five millimeter dial I could use it on there in the groove took a piece of tape around it I'm going to take a second lap look the tape is to protect from the the channel locks that I'm going to use on here but the channel locks aren't biting on the I'm not trying to bite into that the shell with the channel locks I'm just letting the channel locks run up against so I'm just gently touching here and getting to where I'm starting to ride up on the pins like I can feel the pins there now I know I'm actually on the pins so I'll just grab and it was left hand that's why I was having a hard time so so this broke loose it's protected so that that's not going to cause any issues and we'll use the same technique on the lock nut on the spindle once we get it out put the strap wrench on there spanner show it sure would be happy but I don't have one so there we go and this is actually pulling the pall bearing cartridge in between the Oh everything out because it's hitting on the seal ring aspect of this is hitting on the okay so we're through there we're done that's all the further it's out of the threads now we have to tap the spindle gently out of the the housing so a nice thick piece of foam under there because when I'm tapping on the top here you have no idea when it's going to loosen up and fall out it's roughly maybe I'm guessing maybe four or five inches of spacing so that's why I'm leaving this much space on that tap until I run into the foam if I have to I'll just jog up some more go from there so now I'm going to go up on top and take an aluminum rod and tap on the spline shaft of the spindle to tap it out of the housing so I put the drawbar back in - that's why I had the foam there and you can see here now the whole spindle cartridge there is out here's our spindle nose our lock ring our first bearing our spacer set bearing lock nut top bearing snap ring and spline that spine obviously it's not getting any Lube it's not chewed up but it's got the brown fretting type of color on it okay so from what we learned about the preload and the bearings what can you tell me about this situation right here no preload free loads gone these bearings were 20 years old they don't know me a thing I should have changed and probably long ago but this is the first that I've seen issue in parts where it wasn't it was a problem second thing I want to show you is we talked about eccentricity and marks or Chevron's if you look very closely on here you'll see there's a H V there and its mate is right there and that was on there to show alignment of a DB arrangement so those were in the line as I pulled them out and that's what they should be they should be lined up not necessarily on a machine of this precision that they needed to be anywhere in particular in the quill but they needed to be lined up relative to each other you see here I'm using two dowel pins that are inserted in the holes they were in this to loosen that and actually that lock nut was was not very tight I wonder if that was the issue to begin with yeah Wow interesting that now the luck that was actually backed off the set screw was gently snug but that was the that was probably more of a problem than anything but we're this far we're putting new bearings in it spin this off of here dowel pins out there we go for free yeah I've got snap ring just now take this up over these are kind of a interesting snapper a plier that come in handy once in a while they actually stay put you just screw this to open there close it so now I'm closing it it's kind of nice because it holds it without you having to hold pressure on it it's whatever press that off in the arbor press don't need to see that remove the lock ring but remember which face is which so we're looking at this we're saying if there's something identifying they can tell me which is which and yes I can this space is relieved and is finished whereas this is just the rough turn finish so I know which face goes against the bearing and I will stone that that has a little bit of track marks probably from looseness and hopefully the inner races weren't skating on the shaft full we'll see when we compress these bearings off ideally you would press this but this fit shouldn't be crazy tight I have the the vise just gently snugged on the actual spindle che the aluminum is resting up against the ring it's going to press on the outer races and with any luck we should be able to just tap this out using a big orange deadblow on the top these where it says star and - - that's the eccentricity it's also the tolerance on that book on the on the bore and this outer race eccentricity which lines up with the chevron I told you about that's showing that this is a minus 4 micron OD from nominal so from this orientation I'm going to look I'm actually going to use the other one to tell where the eccentricities I'm going to take the spacers off right now and identify it because well I won't matter because I don't have an eccentricity marks on my other bearings but if I if you did have exit Drizzy marks what I'm showing you will be important so I'm going to go through the motions just so you would know if you had eccentricity marks on your bearings this right here this is evidence of poor grease massaging in the bearing and you will see that when I show you how to do that and as you can see here a vast majority of the grease of this bearing is not in the bearing but has fallen down through now I take this inner Esau and we're going to look for the eccentricity marks okay so right here you can see the star the minus 4 as tolerance on the boar but the important part here is is if we were rebuilding the spindle and the bearings we were had had eccentricity marks what we would do right now is we would come right here we decrease this right here and we would put a line right here say hey other bearings the inner race eccentricity marks need to line up here so that's what you would do now in my case there are no our eccentricity marks so I don't need to worry about it just put them together remember I talked about the relieved outer race and that there's almost no lip on the one side of the outer race you can see here that's where the bearing has actually popped in the process of it putting pressure in that direction to put it off the spindle it actually popped out of there there's the down facing side of the seal ring and you can see here this is all iron dust so yeah this is pretty thick but that thing's chugged away not giving any problems so we'll go from there but this needs cleaned up and I might consider an air purge on this one absurd thing about the spindle design is these open holes coming right up into the Celia every little detail matters when you're working with spindle bearings and they're open to have junk fall into the greased ball race area those burrs flappy birds they're from the intersection of the two threads that should never have been put together like this that area should be deferred to where it's absolutely positive that there's nothing free nothing can fall off and get into the bearing so this will get deeper thoroughly before it goes back on again you have to be extremely conscious of these things it might seem like I'm being extreme but if you saw the procedures in a in a high class professional spindle assembly area you'd realize that I'm I'm I'm almost cutting corners in comparison tough to beat the ultrasonic cleaner for cleaning up these spindle ports this does such a thorough job of getting all the dirt out of the nooks and crannies [Music] here are the parts washed but we take the part so far don't leave anything assembled take every set screw out wash things individually look for burrs and Eber all of my comments in this particular section are about the fact that this bearing obviously it would be on the shaft but it's going to be in this general location and this area is exposed for things to fall into dirt particles chip metal chips whatever anything in there that gets in there is bad news so you need to address things on the shaft and nut that could cause issues there this edge right here is totally under bird and has all kinds of little microbrews hanging on the edge that should be filed and bright boy sticked these threads running over the crest of the threads to remove any hairy burrs of any sort that are on that thread because those things as the nut comes down on here can get kicked loose fall right down into the bearing there's the inside of the nut same situation totally under bird area where the chamfer intersects the thread all these little micro chips on the edge here can all fall off as you put the nut on and there screwing it on this nut needs to be chamfered with a scraper to get rid of the main Burr and then a bright boy or Crytek stick needs to be run over these threads especially at the ends here to roll off any burrs and then ultrasonically cleaned I'm taking a carbide triangular scraper and I am knocking the top off that thread that ragged edge there there now the hit threads a little higher I can actually use the bigger part of the tool where it's easier to not slip so let's do a little spindle analysis as far as condition wise what we see here is some fretting corrosion basically where two metal surfaces are allowed to micro rub on each other at very very small displacements that causes a actual corrosion effect sometimes if it's really bad it can actually be a really rusty orange rusty brown color now this isn't bad and this is mainly caused because from the locknut not being tight and this inner race being able to move typically this probably wouldn't happen but it's also a sign of no assembly Lube which i think is very important something I've used in all the spindles I've designed and really helps I'll cover that when we get to assembly but we're also seeing linear striations here that show that this was not assembled in the cleanest conditions because of all these these scratches these scratches didn't just come from from nothing they came from minor particles or a bearing that was not started square and chewed the edges a little bit but these these striations are a sign of poor cleaning and pre deburring of everything before it's assembled the poor design part is is what this is all assembled this is the bearing that came off of here and you can see that the actual internal spindles supporting the bearing only came this far that's all the further it is this is all untouched this is all hanging out in air up here where they just made the bearing area too short there was no reason at all to have this much thread all this distance not supporting the bearing sad part is it's not even making it to the bottom of the race so in essence this the the loads on this or actually it's to some degree unsupported here on the end especially because the contact angle of this bearing this upper back half of the end of the race on the inner race is what's actually bearing so in essence this is pretty much unsupported out here at this so you're relying on the stiffness of the cylinder as part of the spindle design so that that's a real really bad design in my opinion this is the slinger ring and one important design No about spindles is anything that is in the path the clamped path of the spacers races things like this slinger rings everything must be extremely parallel and the reason for that is is if it's not it will actually bow the shift and when I get to the point of actually lapping the locknut for straightness you'll see what I'm talking about uneven pressure axial pressure around the clamping area the cylindrical clamping area of a spindle assembly can severely bow the shafts and has to be accounted for something that a lot of people might not be aware of but you really have to pay attention so that's why very very close parallelism of these parts is very important one of the things that happened in this because we had the situation where we had the race it the inner race clamp ring our luck knot knot tight is that these things were free to kind of jiggle around and get some fretting corrosion and some scuffing all these scuffs and things totally unacceptable to go back together that way these scuffs and drags right there absolutely must be kiss ground we'll look at the inner race the inner race is going to have them on here because the inner race is what was loose so all there you can see there's relative motion between this spacer because it wasn't clamped and the the race face and that has to be corrected so these will get stoned to get to the original surface and then will rotary spin grind these as a match set the outer race will not have those problems because it was clamped it's clamped by the outer ring that we removed to get the whole spindle out so this was clamped and even though clamp doesn't mean that it can't have micro motion that could cause fretting but it means it can't have grouse motion like the the phrase the space are being free to spin around and around in there so this one even though this would get stoned if everything were in good shape precision ground stoned anything I'm anytime I'm saying stoning here I'm not talking about some old shop stone I'm talking about a precision ground stone that would be that would be good enough but since we have to grind both we'll do that another design element involved with duplex pairs of bearings that are match ground is that the tolerance on the total width of these from nominal can be as large as minus ten thousandths so when you're designing a spindle even though 99.999% of the time the bearings are nowhere near using partly any of that tolerance they can so if you're going to design a bulletproof spindle that if it's going to be rebuilt you have to accommodate for your design that if these bearings were ten thousand shorter than the nominal dimension will everything still clear well all the axial clearances and the labyrinth seals and whatever will they still function or is you're going to get metal the metal where you didn't account for that so really important I will measure these to see where they are and when I get to the actual assembly stage I'll measure the other ones just to make sure there aren't any gross differences where I might need to actually measure the internal clearances in the ceiling area to make sure that when I assemble it I'm not going to have trouble another spindle assembly thing is depending on the fits of these bearings and how they go together if you have a mistake and if you have not a mistake but situation where you go oh rats the seal ring is now rubbing the spindle and there's no good so I have to take it apart and do whatever machining we're gonna have to do to alleviate that situation you have to remember now you're going to be pressing this thing apart again and you really never want to have that happen unless it's just absolutely possible impossible because it just leaves more room for the bearings to be stressed to be popped open like we saw where the inner race popped out because of the just the relieve outer race all of those things are just bad you don't want that to happen in the spindle assembly you want this to go together smoothly quickly cleanly without a hitch minimal chance for ambient dust and everything else to get into the bearings get the lock nut on get it protected where dust can't get in it and carry on from there so I you guys might be thinking I'm I'm like overdoing this but this is this is really what precision spindle assembly these are details that are part of precision spindle assembly that if people are doing things you know the right way this is this is old-school stuff of how things are done and I'm sure all of the you know top-notch spindle rebuild places are following all these things and or being even more extreme so if you think I'm overdoing it I'm not in the bearing world they'd be saying well he's he's he's doing you know most of what's there but cleanliness wise he gets an F for even doing it in a in a non controlled environment but if you're careful you can put these together and have no no issues with life from contamination in there in the real world another design flaw that I'm addressing here is these holes they have 13 mounting holes for bolt on tooling on the spindle they're they run right up into the celia was crazy so if these weren't plugged which they weren't from the factory this stuff just comes right up through the holes and fills in there so I've been having set screws in here like the ones I have right here I put set screws in to keep them masked but I want to put something in where these are this is mask completely all the time regardless of whether there's bolts in there or not so just turns out that 1/2 13 it's hard to see cuz of the black but that the half 13 socket head here tightens up the chamfer on the on the screw and the in the run out of the tap matched perfectly so I'm going to use these and you'll see how I modify this to put these in with Loctite I'm turning the head to 32nd under 3/4 so that it fits in a collet nicely but mainly so that it's concentric with the threads so that when I turn this around to do the work on the other side the threads are going to run true throw a call it's stop in so these will go into repeatable fashion so that I can go to my same readings on each part and just throw them in and out of the collet he's off to uniform length [Music] [Music] [Music] [Music] so what am i doing I'm making a breakaway neck here and removing all the threads such that this threads in tightens into the bottom of the tapped hole into the Loctite and then once I exceed the torque of this it's tightened and this snaps off and we're ready to go just doing a test fitting here we've done it before but we'll make sure yes this is below flush and somebody wonder why did I turn the threads off the back here because it would have threaded in just fine like it did before well the problem is since I want this to shear off this has to be able to spin independent of this so if I left the threads on all what happen is this would tighten tighten tighten and yes this would eventually shear but it would be all mashed up then working against each other so this is so that this can snap off all by itself I've sprayed the screws with Loctite SF 76 49 primer just to get them to cure a little quicker so I can keep moving I'm gonna thread one in I've got my wrench ready I'm going to come up here to where i'm in the general zone and i'm only going to apply the Loctite 648 right here in the at the edge here and then I'm just going to massage this to get this to work into the screw real well okay that way I'm not filling the other threads and the other side with Loctite which I don't want now I'm just going to torque it snapped off that's it let it cure there's the snapped off piece haven't you felt that torque I should have left a little bigger but it did the job and there's no strain or anything on those pieces it's just actually a dust plug for all intents and purposes there's the plug viewed from the whole side it looks like it's shallower than it is I have a safe edge ground on one edge of a triangular file I have the lathe running in Reverse and I'm using that edge to dried in a thread and come over and just ride down the the ramp of the intersection of the chamfer and the thread angle it's just an easy way to get a chamfer on there before I break with it then I take the bright boy slow speed really bear down on it force the corner to get in there and take the shape of the thread so I can really knock the peaks off you don't want to stay engage the shoulder or you'll chew all the ribs off your that you're developing on your bright boy stick after a while the prey takes bright boy whatever you just keep reading gauging in that thread shape that forms that really does a good job of deburring that leading edges that I was talking about so that there's nothing to fall into the bearing do not use sandpaper on these surfaces unless you're using some crazy fine you know thousand grit or something even then I should I frown on that precision ground stones is the optimum way to knock the burrs off here without changing the diameter remember these are single micron tolerances of the bearings that are going on here so you say oh what's the paper going to knock off it can knock off quite a bit on this ends a little different story where the bearing actually sits I'm not going to use abrasive paper but here I am because I don't care if this is a little smaller matter of fact it's actually better if it is it'll start on square and and go from there so he's a bright boy stick to chamfer these screws the size of the grooves here get rid of any burrs on there and then we'll see in this is so 320 here silicon carbide and I'm just polishing this section that's not the bearing fish it was ground at the same time it is technically the same diameter but I'm getting rid of all that dingleberries and mix the stuff from snap ring pliers and whatever so that the bearing will slide on there practically hand fit until it gets to the actual bearing pit if we'll hit with the precision ground stones where we're going to use the stones [Music] I can look at this you see we've got chew marks and things here from where somebody got that bearing on crooked and so this good thing that we're doing this this is getting rid of all those high points without changing the diameter I'm also coming up here against the shoulder making sure that shoulder feels nice and smooth there on a dents and dings on it this end is not a class seven bearing but it still can't hurt to make sure we don't have any burrs dents dings of the shoulders good you can see how this precision ground stone is rounding up not rounding up but smoothing up you're getting rid of the the craziness on there yeah it sounds like an advertisement for precision grounds flat stones but they really are that good place I do like these some like 600 paper on is just the very corner here where it rolls up from the chamfer up onto there that can have shape to it and and burrs on the edges that can cause that striation pattern that we saw on there so I'm rolling on that I'm not riding on the diameter at all I'm just hitting on that corner here I'm using the frightful stick to knock the fuzz off the threads especially the lead out of the thread where I had previously deferred that with a scraper you see how I'm letting the threads chew a lead into the rubber block and coming back into that same lead each time [Music] basic way to think about this is if when you're done you can't press your finger hard against that area while it's rotating and not worry about cutting yourself it's not done yeah smooth as silk right there this is the ring we've turned out at 416 stainless Ford turned to the sizes that we want to press on to the to the spindle nose and I've got everything to be bird polished here that got the groove part partially parted and then I chamfered it in the put tool back in so now I'm going to part this off [Music] [Music] [Music] there it is mr. bird the inside edge with a a scraper and be ready to press onto the spindle News people an Instagram we've already seen this but this is my paper adjust system on my punch grinder that I've or less turned into my rotary fight grinder and this is a differential screw arrangement that is the equivalent of 440 threads per inch and allows me to adjust the tilt of this table on the grinder is sub arc second increments really it works slick I put this on and off twice and ground five-inch diameter parts that were less than 20 millions flat so it's really smoking really working well just spraying some alcohol here so you can see the air purge in action blowing out anything that's trying to get into the interior starting off nice year round till I have my wrench opening in line they were indicating ten million per division I'd say that probably a good clean 15 yep end is pretty you so hopefully I'm going to be able to press this ring on without killing it got my how to ring here to get Street on bring this down sand has no some temp to well too bad now I need to push this down just a little further and I believe this ring will sit on just enough to do that just a nudge a very important step whether or not you have used magnetic holding on the parts you're working on or not in this case these because we had them on a magnetic Chuck they must be demagnetized they're going to be a magnet for pulling metal particles towards them otherwise so everything should be demagnetized [Music] also a good time to point out don't use paper towels or toilet paper or anything but lint-free wipes when you get to the final stages of assembly a huge amount of dust falls off of paper towels toilet paper is really bad a lot of them is really bad for just shedding lint so it's very important final assembly a final cleaning and things only use lint-free wipes they're not that expensive okay here we are geared up for massaging the grease into the bearings I have a tray with a lip on it all the way around very important sometimes it's easy to slip with these bearings occasionally you might drop one so if it drops into a pan with a lip on it all it's good if it drops onto the lathe and rolls off into the chip pan you got trouble so this may seem extreme but for a home shop or non cleanroom environment this is the steps that I think most spindle and barring people would say yeah this is this is good practice so I've got the lathe covered with the my vapor poly vapor wrap just because it's something I have that's clean and can be cut the size stretched over the nose cap of the HL VH I have a PE T plug that has been turned where it's just a snug fit on the idea that barring I have my scissors ready to slit the bags I have my massage tool which is made from woolly mastodon tooth very rare but it's the only thing that will work on this and do it well not really it's Delrin but one very important point about making these is do not use an abrasive process to shape this thing because this tool is going to go in and be bouncing around on the bearings in the cage and everything you do not want any possibility of embedded particles bracelet particles in this so brand new file whatever scrape it for the final things with just a razor blade make sure there's absolutely no possibility of abrasive particles everything gets wiped down with kimwipe and alcohol and then we're ready to go typically what I'm going to show you here as far as massaging grease is vastly more important when you're using a channeling grease that's a stiff grease more common in high speed spindles the Kluber nvu 15 is a slumping grease and even though you'll see that this there's there's a good reason to do what I'm doing here it's not quite as important you can you in theory with this grease you could probably get away with just running these but you'll see as this spins these will tend to extrude grease out that comes out and into the off you know past the faces of the bearings and you'll see that with a little massaging you can get it to where the the grease stays internal to the bearing and is covering all the areas nicely you notice the box is missing now because the box is cardboard and can shed cardboard fibers so the I've blown these bags off to make sure nothing's clinging to them and after this point they were going to stay in these bags only you want to slit it as close to the seam as possible to leave it room to flap the shut for protection when your once you're doing that I'm wearing clean new gloves take the bearing out we're going to slide this on the the mount here I have it mounted on the plug it's just a finger press onto the plug only goes on a little bit I'm wiping off the excess protective oil off the outside and now I'm going to hold the bearing turn on and we're gonna let this turn I'm pre-loading the bearing gently with my hands and I'm gonna turn this off a second so you can see what happens see how this grease is piling out here on this face well our job is to make that state back in place so I turn on what you do with your massage tool is obviously have to lay at the right angle you just guide and form this to go back into the bearing push up just gently touching the balls and push it back in so it looks wonderful except that when I pop this off and go the other side you'll see all I did was push it to the other side so go back one thing go back on same thing now we push this back in this side gently making sure we're trying to get this to go into the bearing and not just scoot off into space pushing it back in and I like to go around the outside on the outside you get some around the tracks of the balls and you can see this is pushing out again [Music] shut off flip plus a little tighter than I like but I'm not gonna do anything with it right now hey you can see on this side it didn't push it out quite as far and what you do is you just keep going back and forth probably take Donna I spend a good five minutes so on the bearing typically to get it to where I'm happy that the grease is is content as you see on this side this wasn't as plain as drastic and let this race slide a little bit push some of that back into the relief side scooping it off the face of this the retainer and now I'm not pushing it in quite as far so I'm trying to get a happy medium here where this is going to stay put you can see with all this handling of the bearing when I said about having that pan there so in case you drop it it's not not a I'm not kidding pretty easy these things you've got grease on your hands they're being slippery so easy to leave you have a drop [Music] on smaller bearings some of them I just use a urethane cone doesn't match exactly and I just press it against the cone but bearing this big can get out of hand real quick one up on just a cone so on the larger ones I use the shoulder plugs like you see here now let this spin again push that beast back into the actually gonna take some out to that side and now this a channeling grease is really stiff and it it's called channeling because it forms a channel where the balls ride but all the ups dressing the grease is nice and stiff and stays there and just makes like a wall where it's gently feeding right into the interface between the ball and the race so it would be a completely different look than what I'm doing here with the slumping grease but as you can see here I'm getting to the point now where this is this is starting to behave I'm just touching that side over the other side see how that crease is pushing back out after I push it it's kind of like it wants to come right back out again and they push them out the outside [Music] you can see how I just guided that grease out to the outer edge and now I'm taking it in so that it goes all the way in and touches the balls [Music] [Music] okay I'm gonna call that done as you can see now we've got really good intimate contact the grease is really wetted the retainer well we'll go to the other side same thing on this side and from what's left on here now it may sling some out but it's it's a whole lot better than it would be if I hadn't massaged it now back into the plastic hold it shut just leave it sit here dude number two and carry on another view when done to is the quill housing and obviously you'll need to clean that very well get all the old oil grease whatever that's laying around in there should be perfectly clean I called in the professional quill housing cleaning experts to do this job take it all the way out right so they could see the what we have on the end just have a foam plug on there to be able to go up and get a tight fit on there getting the worst out right now dry and then once we get all the crud out we'll clean with alcohol and then we'll go back in with just like some LPS 3 to coat the walls so they don't rust I have my hot plate set for 140 here and these bearings would probably hand press on but there's no reason not to just warm them a little bit make sure that they go long without needing to use the arbor press I'm putting the bearing in here on some Teflon lined aluminum foil you notice I've got the flap there to cover this we don't want any exposure to ambient dust falling so they're sitting on there to just warm up stay nice and covered I use CMD extreme pressure Lube number three to lube all bearing fits it's a very high pressure high film strength Lube it helps to have the fits go on easier and it also helps to diminish to a fair degree fretting corrosion if the bearing fits aren't quite what they should be so in my mind definitely a good a good thing to do all the spindles that I've built all the spindles that the company that I used to work for Bill's still uses this technique it's just good practice I don't know what the industry's thoughts on it are but we know that it works well just need a very very thin film you don't want a bunch on there and that's all it takes I'll do the upper bearing area now all the other surfaces that are exposed have been all degrease super clean and they could rust so I usually use something like LPS three wet a kimwipe and wipe all the surfaces they're exposed so that they have this nice waxy long-term lubricant on to prevent any corrosion inside the spindle I'm going to be putting blue moly on the spline section later all the other parts that have been ground have been demagnetized precision ground stone and now we're just putting our light layer of rust preventative on here so this is basically clean ready for assembly and put over here on the clean kimwipe remember at this stage absolutely no lint generating towels no bounty no toilet paper no shop towels only lint-free wipes like a kimwipe but it doesn't have to be that brand I don't know what else there is that is lint-free I'm sure there are ones but yeah lint-free towels only and we're just wetting the surface with this LPS three all it doesn't take the net be sopping in it it's just so that it's wetted and it will keep these from rusting these doesn't need any extreme pressure Lube or anything that's a little bit drawn we get some more so no this gloves gloves only because gloves are easy to clean way cleaner than your hands so this all these parts now are coming over to the clean enough to assemble area like I said yeah this might seem extreme but any spindle rebuild place that's professional would look at this and saying other than working in a clean room this guy is attempting to do everything possible to make this a good spindle assembly so this compared to other things you may have seen might seem like wow this is you know you're just going to the extreme here and yeah you can cut a whole lot of corners and spindles will still function but I'm trying to show you here best practices and you can always back up from there okay it's time to start putting things together very important to completely understand the sequence that your parts go on and be totally sure that you know what goes where and with a lot of parts your there's a possibility of which sides which is it this way or this is it this way some parts will matter especially in seal multi-part seal lip areas so I know that this goes on next after the main lock ring like I said everything's been lubed up here okay that's sitting there now next thing that's going on is a bearing and here's where you want to be absolutely sure that you know what you're doing so from our previous discussion I know that I want my outer race stamp face up because I'm doing a DB arrangement between the two bearings of Rowan here so since the stamped faces are going to be touching in a DB arrangement it's going to be up on this one and it'll be down on the one on top so I'm going to go over and get one of the Waring's that's warmed up over here make sure I've got it in the right orientation staff face up Oh baby that's the way it should be now as a lot of you guys know that initial starting point is extremely critical I made that look easy and it's not that I don't ever get stuck but I know what to feel for in that initial stage yet be very gentle and feel for squareness or you can get cocked and once you get cocked especially with a bearing that's been warmed up you're you're in trouble so next thing that's going on we know now that all right it's just spacer time just a wipe with our gloved hand here and make sure that we're clean on the two faces the only thing that's on those bearings is grease on the faces so we're good to go here this should be just a slip fit which it is feels good I'm not feeling any grit or any junk time for the outer race spacer line up get it lined up the best I can and now it's time for the upper bearing but now we want stamp face down I should be seeing the relieved outer race on top because the relieves side is opposite the stamp side relief side up stamp side down same procedure beautiful that's it now why all that I don't want to go over to the arbor press the arbor press is dirty I have to do a lot of cleanup in things over there if I have to go there I have to make sure dirt doesn't fall off of it when the arbor press clunks and all those things so there's a huge advantage these in that little bit of warmth that was only 140 degrees a little bit of warmth to get those to see is is well worth it next is the lock nut and this is especially important on the face of the lock nut to put some CMD extreme pressure Lube on that face because this face is scuffing on the bearing face and I'm going to I wish that this would go together and not need any influence and this is something that most people don't mess with and probably it could be ignored or and spindle but it's a good opportunity to show you what scraping or lop lack lapping a bearing lock nut entails so this is going on we'd already did our crazy deburring on there to make sure that this is why I was so whacked about getting all the birds and everything off of these things before I put this on here because we're working right here where that stuff can fall right into the into the into the balls and that's not a good thing so we're gonna put this on you're just going to Snug that gently putting drive keys on little lock tight 2:42 putting the drive keys on now because even though I am going to be hard turning this taper in running in its own bearings after assembly in order to get the absolute best run out not to mention this taper was from the start this was a a load switch out spindle and it it was kind of dinged up I'm putting these in so that whatever the distortions there are from tightening these bolts relative to the taper those will be machined out since I'm going to be boring the taper in in the machine running on its own bearings using the CNC to go through the tapered path and this way whatever distortions there is and there is some from these screws being tightened will be constant will bore it everything will be good I have this upside down because if I doubt whatever particles or anything that could happen from me using this channel locks on here these channel locks have been wire brushed severely blown off super clean so but by putting it upside down everything can just run to the bottom and I'm gonna torque this up okay that's good and tight now we need to check and see if the nut needs to be lapped or scraped both terms were used some lock nuts they actually it's hand scraped them but lapping them on a plate also works well alright this is a rickety setup but it will show you the principle of what I'm doing relative to checking if this lock nut is influencing the spindle or not I just have literally finger tight is the jaws against the bearings and the end the spacer here my son is holding it down tight against the vise so in the in this plane we're constrained by the vise fairly well so what I'm doing is I'm indicating in that direction and I'm gonna get here where I can get my indicator to to see what's going on here and I'm gonna reach over and turn this now and if that lock nut were severely out of square we would see a huge amount of run out here but that's really good right there and what that means is the axis of rotation formed by the front duplex pair relative to this bearing seat here is good if that luck nut were a thousandth out of out of square we would see an influencing here and then what we have to do is we have to mark the low point where the nut is pressing the hardest bending the shift in the one direction lap it put it on back and forth back and forth sometimes you hit it a few tries sometimes it takes a long time but this is proving that we're good to go that's excellent right there that notes this if this had five thousands run out what that means is when you assemble this whole thing the bearing the duplex set down here would be cycling this bearing would have five thousands around it's literally fighting that bearing every revolution that's not good you don't want them fighting each other unfortunately I didn't get a chance to show you physically doing the scraping or lapping and lock not thing for correcting for out of parallelism of the nut face or stack up of other parts that are out of parallel so I'm gonna give a little diagrammatic explanation of what's going on it's a really important concept in precision spindles or any assemblies this would apply to old horizontal milling machine Arbor stack ups with spacers and cutters and all that this is what can cause run-out and shafts like that so here's the shaft example that is the shaft is perfect the shoulder of the shaft is perfectly perpendicular to the axis of the shaft every spacer is absolutely parallel and every bore is absolutely perpendicular to the face of each parallel and the functional face of the lock nut is absolutely perpendicular to the pitch axis of the screw as I said that pitch axis of the screw and the actual thread axis and the threads on the shaft that they're axis the actual pitch circle axis is perfectly parallel to the screw so when you tighten this together the force that the nut applies is uniform around the circle here around the shaft it's perfectly uniform and the stack up the distance of the oles is perfect the shoulder is perfect so this shaft does not have any influence to bow from uneven forces around the the circumference that we're talking about axial force put on by the locknut compressing the these parts stretching the shaft and if all these forces are uniform and all these parts are perfectly parallel everything stays straight but in the real world you can have it any combination of problems you can have the shoulder of the shaft not perpendicular to the shaft axis you can have spacers that are out of parallel or parts this could be bearings spacers anything just represents a part in the stack up you can have a part that is parallel the washers parallel but the bore is it is a very snug fit and it's not perpendicular so even though the thickness is good it's tight on the shaft so when this what the spacer comes down and touches it's bends the shaft because of its tight fit on the on the shaft so I've got an example here fat fat thin thin ok if you just tightened up on those obviously the thicker side thin side this is going to push and this shifts gonna bow in this direction here I show where if you could selectively adjust the highs and lows and they were all the same you can have them cancel each other and be ok up here you've got your lock nut shown exaggerated with the thread pitch axis which is this being not perpendicular to the pressure face okay this is where the thread lock not scraping or lapping comes in play let's say we have this situation over here everything is perfect except the lock nut so you know all these parts are parallel the bores aren't interfering with everything is square there's no good reason for this thing to bow other than this lock nut is out of the faces out of parallel and what that does is wherever the high point is pushing down this way puts more pressure on one side than the other and it bows the shaft significantly we're not talking about millions here I mean it can't be millions but we're talking about several thousand depending on the shaft configuration how big the shaft is it can cause that issue so what you do you put the locknut on you tighten it to the torque that you're going to in the end you see where the influence is where how this thing's running how this yes being bent and at the low point if you're indicating here the low point here you know okay that's the place where the nock nut is pressing hard because it's high so you mark it you mark it where it is in the shift you take the lock nut off and you go over and you lap on your flat plate you lap influencing to try to hit the high keep it flat but get remove the high lower it down taking the temp put it back together okay yeah I improved it but not enough now as you do that that nut position is going to change so that high point might move on the nut every time you remark where the high point on the nut is and you keep going back and forth so after a while you can get this to where you get this shaft running absolutely straight no you know insignificant TRR running on the bearings it here in this case you could say the bearings that are right here if these were bearings then this axis rotation of the bearings and what the chef does out here like we showed in physically on the mill spindle that can be influenced by this so that's that's what the scraping or lapping locknuts is all about lapping is a lot easier I have a surface plate with silicon carbide paper glued down on it and when you all you do is you put the ring on there and you put pressure more pressure on the high point drag circular or whatever and very gently remove material it's very sensitive you can really tweak shafts around a lot so that's what this scraping lapping locknuts is all about it's to get an assembly to run true by balancing the axial forces that the nut puts on the shaft here's the pathetic pieces that they had in the lock not to go on the threads so ditch those make some new copper pieces to go in I'm holding the spindle by the shaft so any forces I put on this are going to be absorbed directly by the chef they're not going to go through the bearings I'm putting the quarter-inch copper pieces I made but I'm coming over here and I'm taking a hammer and I'm really whaling on this for the copper to really take up on the shape of the threads because I don't want to try to get that to happen by me tightening the lock nut all I'm going to do is stretch the lock nut oval and end up you know accomplishing nothing because it doesn't have enough oomph so by doing that where I take the hammer and actually swage the thread form into the copper before I put the lock nut on now I've got my 242 lock type on my set screw now my set screw just needs to be moderate tension just enough to keep it in place that it's not going to spin and that's it and I'm not deforming the lock nut out of shape okay let's see if we can get the upper bearing on as easily as the other ones when lunch without arbor press oh yeah that was 150 Fahrenheit little free snap ring information once that brings most of them there's the die break side that's rolled and there's the break edge that's dead sharp you want to put this dead sharp edge in the direction of thrust pushing this way because it's nice and flat this rollover is actually kind of like a ramp action that under high loads could actually skate and have more of a tendency to jump out of the groove or wall or the groove over so an important detail if you're looking for you know every little nuance once you've got the lock nut on and everything is buttoned up there I suggest wrapping that area right there with tape temporarily while you're working with it that way nothing can fall in to the bearing and cause issues I know that to those who follow me this is going to be a real shock I'm I'm putting blue Molly on the spline because it was really dry and a little fretting corrosion going on so this is this is just about the ideal lubricant for for that situation wouldn't recommend it for a super sensitive drill press type thing because it might be a little draggy but for this it's perfect so set up here in the middle I'm resting on this seal ring not on the end of the spindle very important point we'll cover that as I get closer so I'm just going to jog down here slowly until I'm about ready to run into something and then I'm going to push up with my hands to not risk anything else come up and get into the spline up there there we go all right now I'm good job down now that I know where I am it I'm engaged with those things it wouldn't be safe to just jog onto it not knowing what you're going to run into I got my finger in a different spot here or I can't get pinched a little slower jog okay now I'm gonna let this down I'm still engaged in the spline I want to make sure I'm not yeah I'm not fighting anything notice I left the blue tape on to this point in case anything fell out we did do a thorough cleaning job but now I'm going to take the tape off no sense in having that exposed to get dirt in it till the very end all right now we already put extreme pressure loop number three on the inside bore of the spindle or that quill housing not the quill housing the quill body itself but I'm also going to put that on the outside here we'll come back when I'm done that so now I've got my extreme pressure Lube on the outside of the bearing stock there I'm going to lift this up in I feel like I feel what's going on oh baby oh that's nice so you saw that this linen pretty well all till the the threads caught because of the slinger ring that I put on the outside of this to make this a smooth diameter there's very little room in this there's only about 1/32 inch of play of this ring before it runs into either this or runs into the threads so I spent about half an hour wondering why this thing wouldn't thread in forgetting the fact that this is left and so so now realizes its left hand and that this presses if you can press gently with the with the quill feed to push things up in there and doesn't take a you know anything more than you know firm drilling force to get the whole cartridge assembly to go up in there that's fine but if it's tighter than that you got to make sure you press on the on the outer ring only on the seal ring here which which is actually bearing on the outer races so I have the threat engaged left hand and now I can just wind this in and the the ring itself will pull the push the bearings into the up into till they seat until the shoulder seats which is what we what we want to happen you always want to check for for free motion when you're putting things together before you get everything totally in make sure that you don't have anything binding that your labyrinth seals if you're putting a new spindle design together or something you're always checking to make sure that nothing's interfering starting to bind up and obviously in this case this is was already together before but we did make some changes so it's always good to pay attention and be be sensitive to things needing some adjustment but this is fine we're just going to rack back this thing up until the ring touches and then we'll firmly tighten it it's important to tighten that lock ring good and firm because it's holding the outer ASIS still that's it's keeping them firmly engaged in the in the housing so you do want to tighten that firmly the set screw that keeps it from from vibrating loose you don't want to tighten too tight okay now we've hit there so the other important thing to check is make sure that you have a gap here because if you're tightening the lock ring into the quill that means it's not clamping the bearings so always check make sure your lock rings have the clearance gap that they should not it's not an exact amount is that there is clearance so that you know that you're clamping the races so we'll tighten this up firmly we'll put the set screw in the back and we'll move on to setting up to hard turn the ID of this running in its own bearings so that's why we could care less about what kind of run out says this needs to be skinned anyhow so we'll set up to heart turn it so here I put a CBN tool in the vise on the mill and just skin the surface of this and all the variation you see there this is where there's no support under the under where the keyway is and then all the other stuff is just the shape of the outside of the spindle I guess deformation from heat-treat or whatever that's got that sheep because the shell was really parallel but basically got all the lumps and bumps off there so that my seal ring my air purge ring can sit on there and not rub here's the modified ear ring got a little miniature banjo fitting here going in and then this is drilled through into this plenum area this Delrin or PT is impossible to get a well not impossible but tough to get a good image on so I'm going to go down here to the cross-section that I've got drawn here and describe what's going on this ring I made before just as a protective ring to keep the dust and things from getting into the quill area up where it actually goes into the quill housing and it was never intended to be an actual seal here but it did it did it does a really good job in keeping the dust off there so in this spindle rebuild you saw that I made this steel ring to press on to mask where the drive key slots ran out to the edge here because I wanted to turn this into a actual air purge seal so I just want to show some details of some of the design thoughts that go into an airport seal that this isn't anything magic I'm just showing you the the points that I'm thinking of what I'm designing this number one you don't want the air to back travel through the spindle because you can if you have too much air flow through a spindle you can literally slowly blow the grease out that's a bad thing obviously so right here I have about two thousandth of an inch clearance and you see I have this like knife edge situation going on and that's because there could be contact here if I left this just cylindrical and there was a rubbing situation going on there this thing could just melt smear carry on and turn into a mess by taking these down just to that very fine knife edge what will happen is these will just melt locally in this very small area leaving a minut clearance and give us what we're after which is as close to the no flow this direction as possible on this end down here at the bottom we have a gap that's about two and a half times larger this gap is about 2,000 s this is about 5,000 SCAP whole purpose being the air would rather escape the the path of least resistance which is going to be this side so can there be a little bit of flow this way yeah but predominantly it's going to be this way and you have to have pretty significant flow to push grease out just a very slow leakage type thing is not going to push grease out then we come here this right here is very important if I didn't have this here and I put this air line coming into this what what happened is the 99% of the air would flow out just in the local area where this feed line is by putting a large plenum full circle around the spindle this fills and becomes a chamber that then feels this little bit larger smaller gap and then finally this gap and that all that has a tendency to make this come out as relatively uniform pressure as looking around the entire gap the pressure will be immensely more even by having this large plenum so just some of the design features in thinking about an air purge ring in designing spindles to work in a grinding environment where you literally are generating grinding grit by grinding a wheel down with a diamond roll and high pressure coolant you have to learn pretty quick on how to keep keep things out of a spindle so air purge is probably one of the best but they need to be designed correctly to really be effective it's not just a an airline into the spindle that's not enough is the air purge ring on you can see my banjo fitting right here that's going to bring the air in and I had to add some additional set screws to be able to tweak this lip clearance running a 2,000 shim around there to make sure that it's not dragging anywhere and that's because the OD of the lock ring that this is riding on is not necessarily concentric with the quill there's no reason for it to need to be and it's only guided by the thread so there's all Center just enough that it needed to be pushed around a little bit until this shim could pass everywhere so it's not rubbing a little quick working to call it turns this f13 flathead socket tap into a custom screw you've answered the holes here when they're not used here I have the organ bar that I've made this low carbon built a slot put it in the CBN tool ground and lapped it I've aged found on the face of the tool to get the spindle on Center for Center height if it was a lane and then I've ripped parallels I've got it balanced here with the parallel to each side I've got a piece so that this hits on the on the OD of the bar purpose of that is I've got the sandwich in from both sides so that if I have to re lap this bar do another left job on this before the final cut I can slide this out it's very snug I can loosen the vise slide this out go map it slide it back in again and it will be back in position very very close they don't have to do with minor adjustments instead of being in the middle of nowhere and having to pick up all over again so you SolidWorks to do my geometry here the taper fork at 40 is 7 over 24 so I used the sketch to set these dimensions horizontal and vertical to set the line at the correct angle which is turns out to be 8 degrees 17 minutes 50 seconds and then I took my heights of where I'm going to touch off where so I actually start to engage the taper this is the where the actual tip of the drive keys are so this just gives me the geometry of exactly what my moves were going to be in the program be very careful with using the mill for as a lathe because a lot of things are backwards as far as X&Y it's kind of confusing you're driving the head instead of the tool and it's just easy to get crossed up so really double-check your work they just touched off there but has turned off and zero went out there now that we've got the taper completely cleaned up I'm gonna loosen this Center vise like I discussed before and slide this out of its pocket and go lap the cutting edge again for a final pass see what this looks like under the microscope whoo laughs this again to be dead sharp and then we'll just take the nice final finish pass this is why I always have these flats on the bottom of my boring bars to be able to grind and laugh using that as a reference some have like one micron diamond here on a one upon a brush with some mineral spirits and I'm keeping them the lap face wet and just when I slowly roll around the nose radius here with the Malloy micron and improved the finish on this this bar was barely worn at all all that material we removed that not not effective hardly at all with the cutting but there's a significant difference between the finish and the how the tool lasts between using three micron one here in one micron 1 micron really leaves a mirror finish on on the CDN for carbide I like this brush technique it otherwise as your joint if you put stuff on here just all piles up on top of the tool and screech softly you're not keeping the lap charged with Priya Priya braces too to get in there there are other techniques of using this totally dry we're really really flying finished and the face of what happens here is whatever's charged and lap starts to break down and get finer and finer and get substantially better finish than what the diamond have did normally a little bit of forethought about the relocation of this bar was worth its weight in gold because now you can see that's really snug between the parallels now I go down touching the bottom like it was tighten this up and I'm right back in location darn near like us if that was in an alura's tool post huge time savings I would have to go back spend probably a good half an hour finding out where I was again inside that part if I didn't do that so that's a major tip there as far as saving time I'll pass 59 syndicator here and that's one of the advantages of grinding after assembly is basically just getting that down to the minimum Rumble you'll notice here my measurement loop directly coupled to the spindle housing down through here I'm not down on the table with some long extension where I've now included the entire machine frame in the measurement loop I've shortened it pretty much as close as it's gonna get if you made it this far non-stop you really need help that's that's that's a lot of stuff to sit through but hopefully the information there was useful and tell your friends share and I'll be back

Channel: ROBRENZ

Views: 505,183

Rating: 4.8494353 out of 5

Keywords: spindles, spindle rebuilding, precision spindles, spindle design, spindle

Id: grUdsTTRGl4

Length: 94min 22sec (5662 seconds)

Published: Sat Jan 18 2020

Reddit Comments

[u/Krikkit_Jelly]

It's not your conventional artisanal fare...

But there's no doubt in my mind that this kind of high-precision work is every bit as skilled and challenging as many of the trades with much more visual/aesthetic Wow factor.

[u/secretsuperhero]

This is the kind of stuff that I love

[u/iC-Sharp]

Look at that meter thingy! Cool!

[u/juxtoppose]

Was that millionths of an inch or millionths of a millimetre? Wildly impressive either way. That’s different reflective properties in a certain light type of shit.