MAKING ULTRA PRECISION TOOLROOM SPINDLES #1

so what are we talking about when we say tool room spindle this is anything like a harrog grind all or a suburban tool uh spin fixture anything that rotates the part typically has a 5c collet or a an adjustable v-block that's the type of thing we're talking about so this is the version that i've designed and i'm trying to get something that's quite a bit more accurate than the standard one hopefully down in the 5 millionth tir range uh or better so this is the construction of it we're showing the bear unit here and now you're seeing it with the 5c collet adapter bolted on the front this outer ring has adjustment screws that will act like a buck chuck to be able to tweak in the trr of a collet after it's in there and the lock nut for the collet is in the back here here in cross section you can see how the nut bears only on the inner collet body not on the spindle because pressures on here with the collet tension would affect the preload on the bearings this is all hardened a2 tool steel with the bearing races lapped directly on the material and we're going to be using grade 5 balls which are 5 millionths roundness and 10 millionths match in size for the entire lot so there's a lot of balls in here to give elastic averaging so all those roundnesses will elastically average out and should give better tir than it would with a lot larger less larger balls here we're showing a magnetic chuck mount where i have these eccentric pins and the pull studs that pull this back against the chuck blind this is a about a four and three quarter inch chuck and then i also have a 10 inch chuck that will mount on here with the same pin system and there's 12 of these evenly spaced around here you may be wondering why there's so many holes here but in high precision applications the influence of the forces that the screw puts in the bolt uh holes will actually distort the shape of this if there was only three holes in here this would start to take a trilobial shape and that would influence the accuracy of rotation since the races are directly on the shaft so by putting multiple uh closely spaced smaller screws and distributes this out where the deformation starts to overlap and this will be much more round and uniform both facially and radially than it would be with lesser screws and you can see the outer bolt circles also have 12 as do the eccentric lock style in this video i'm going to cover the general machining of the main components here and other videos will cover some of the other aspects of the construction of the eccentric pins and some of the attachments first we're going to take a look at machining the housing very simple part actually very few details on here yes there's a lot of tapped holes but other than that the geometry is very elementary here on the roll in getting ready to cut the spindle housing to size it's already on size on the clamped direction using the digital stop i made for the roll in awesome you guys definitely need to make one of these really really handy facing off the first surface of the block using face mill obviously it will get flipped over on the other side done squaring one edge and they'll all get uh squared up putting a three-quarter hole in through the whole part so that i can dive in with my insert cutter uh which doesn't end machine all the way as you can see here this lets me dive in the center and just use a pocket mill routine to rough out all this material and we're doing this to both sides to remove the mass material then we'll go on the lathe and hit those parts from there now we're doing the central bore halfway through there it is both sides finished we're going to grind the two large faces of both housings we're doing uh two different sizes of these at the same time and uh stoned the chuck stoned the pieces put them on and these are going to get ground together grinding one side we'll flip them and do the other side just the same still leaving a grind allowance for after heat treat now we're going to square up uh one edge in both directions at once i have a spi hardened magnetic v-block that i bought long ago and this thing is really just probably one of the most useful grind tools uh that i have it's extremely precise as is and i have re-lapped the bottom once where it has worn just a little bit but it's basically dead nut square in both directions so by putting this on at a 45 degrees i have my little plastic protractor here and i'm taking my five inch distance of the first piece and i'm saying okay i want to get this for my center of my grind stroke wheel center down here is is roughly right there that puts me where i'm the same crank and a little bit further so i'm saying five inch two and a half i'm getting this lined up that's the bottom of my crank so that my directions both ways are the same just makes it nicer for grinding okay now that that's on a important note relative to using anything like this that's a reference whether it's a precision square a tool maker's knee whatever it is you always want to support the center of gravity of the part you're putting on there on the chuck so that they're by doing that you take all bending loads off of this because now all the weights being supported here at the center of gravity so there's no moment loads like this pulling on this part everything deflects it's just a matter of how much so by doing this i'm going to put this little steel chiclet here two and a half by one location center of gravity of the part turn this on wipe my bees i take my part now and i'm going to stone where this is going to sit on this first side and now i'm going to put this in get my on off switch here and i'm going to put this in and put it in just with a little bit of magnetism on and turn this on just a trifle so that this is being held now what i'm going to do is i'm just going to tap this down now i'm sitting i just want to make sure you understand the principle here by putting a support at the center gravity this part there are no longer any loads if if i if this was a angle block or whatever and all i did was clamp it sitting in midair now this weight is pulling down it's putting a moment load on this and it's deflecting it here i basically have not altered the accuracy of this block at all because i've taken all moment loads off of it so important concept we're going to grind this and then we'll flip it and do it again we'll have two sides perfectly perpendicular two directions advantage of the v block is we're doing two directions at once i'm getting squareness to this face right here between these two faces and i'm getting squareness here simultaneously so that's the beauty of the of the v block now we're doing the other side perpendicular to the side we just ground so we're resting on the ground face putting it in lining up and then we will grind this face and once this face is ground then we can just put these other these two faces on the chuck and just grind parallel we don't have to use the angle block anymore but this gives us squareness in both directions very easily measuring the height remember we're still leaving material for grind allowance on these sizes digital height gauge is really handy for that now we're moving on to drilling the tap tools we're spotting here not showing the entire pattern just enough to get the idea now we're drilling a tapped hole for all these and now we're drilling the counter hole for the thread release now we're spotting the air purge holes down in that little lip have to be very careful about the spot drill not moving off now we're drilling the actual hole that will run into the hole you'll see in the next picture just a little note here about uh cross drilling and threaded holes and things this is really a place where some little flappy micro burrs can form and if you think about the function of this spindle ultra high precision tir and you're going to blow air through here as an air purge when necessary any particle of metal that could dislodge and all of a sudden go through that gap even though this is designed to be after the bearings uh would be not a good idea so that's why i'm taking a little diamond ball burr as you'll see here to do the deburring in the bottom here's one of those cheap diamond plated mandrels that i've turned the neck down on to be able to get in here and do the deburring you saw there so right here in here i can put that bulbur in and sweep that until the edges get deburred and do that to all the holes because the same thing applies there any little burrs or anything that could break loose after heat treating would be problematic doing the same holes on the other faces spotting this pattern matches the renzetti pattern this is the tapped holes and now we're doing the counter drill hole and you'll hear why we're doing that now you'll notice that all of the holes that we put in these fixture parts that are hardened steel have a relief diameter here which is really just a drill point and that relief diameter is a little bit larger than the od of the thread in this case quarter twenty so this diameter you see here is the tap drill but this is counter drilled down through this about one or one and a half pitches of the screw to make sure that this doesn't pop out from the loads that occur right on the edge of the part remember that as these tool steels get hardened they get a little bit more brittle and the essential screw stretches in the process of applying tension the heaviest loaded lead of the thread is right at the face and the next picture is going to show you what happens when you don't do this to a hardened tool steel piece as you can see on this piece those broken out faces around the screw holes are from not putting that relief around the screws so it's a very important thing on hardened parts i have the larger housing on the sixth jaw now these were just roughed out with a insert mill as you saw before now i'm going to finish turn these before heat treat i'm going to be leaving ten thousandths on each surface to hard turn and grind and lap afterwards so we're coming over here and i'm just double checking my my tir facial this is just how i stuck it in the chuck and we're running less than a half which is plenty good enough because this is like i said this is still somewhat rough one thing to note when you're doing something like this i'm going to be indicating this part in and indicating directly on the flats here you want to line the flats up with your adjustment screws for your buck chuck or set tree chuck style bus adjustment screws so that you have a direct relationship of the movements rather than having to jock him around and not have a one-to-one uh you can do it the other way but it's just a lot more makes life a lot more difficult so now i'm going to set up to do indicate on top here and i like to get just a little bit in towards me from center so that i can use the cross slide to do the fine tuning and and you'll see technique-wise what we do here so i find that so i can ju just now just by moving the compound in i have a very fine adjust of getting on zero without having to touch the indicator so that is my zero on my two and go to my opposite to my four come in and see where it is wow amazing oh that's just the way it was on the chuck um okay that's a half high on this side we're about one low speeds that should go down and then i'll come crank up on my one three side well it's these numbers i'm referring to are the numbers of the of the actual uh adjuster screws so i'm half low there over here and on here so we'll release this a little bit and remember this is a matter of fact that was just not even tight so i'm just going to snug that one notice my camera and i'm going to jack this one a little bit snugger and this isn't it this doesn't need to be dead nuts because like i said we got ten thousands we're leaving on here so that's plenty good enough for what we're doing and for those who might not have seen it before um all my machines i have a post here that is the same as the post on my magnetic base uh and i have my fine adjust captive fine adjust here that's a flexure so there's no joint slop or anything this is really really handy if you you i mean i do tons and tons of indicating and putting a magnetic base on and off the machine is just silly when you if you do a lot of it um it just pays to have a post there ready to go it doesn't interfere with anything um and it just saves a lot of time and the people that have adopted this uh agree it's just it's just really really handy before this side the other side's already done i'm just showing the operations on this side i already flipped it once punch in my tool number and my target dimensions say 20 away for my last cut stay five away on my face climb up face i would normally use colon i'm just doing this you can see what's going on okay i'm out here go to my zero size [Music] this particular diameter will not be cut again this is clearance so this is we'll stay this way after heat okay come into my actual finish z which is leaving ten thousandths on that base for hard turning and laughing okay get off of that come into my inner bore [Applause] okay come to size which is ten thousand small and then i will be ready to crank off the ink off the bore as i trail off here so i don't need a big mark go out to our size lower here we're going to run in here and do our so we don't have a stress riser in that corner we've got a full 30 second radius there a2 isn't real notch sensitive anyhow a little bright boy stick get the fuzz off knock the corners and we'll take a piece of breakaway and go down here into the corner and polish the radius so that that is a nice smooth surface so that no cracks or whatever we'll want to initiate there there you have it that's ready for heat treat that will be lather rinse repeat on the smaller four inch square version and same tool same procedure here's a big pile of a2 rounds for the spindles that we're going to knock down with the tormach and the harding i'm going to tag team back and forth between these two using the old rotor brooch here with coolant fit in from the back and a pinch style uh three quarter diameter boring bar holder and taking the slug i'll do half from this side half from the other and then i'll go around the tormach and finish pouring these is inside the tormach i have two tool posts on at the moment and uh just using this as a manual lathe basically with the um conversational programming which is really handy so i set my compound at 24 degrees to machine the taper on the collet nose adapter for the tool makers spindle here i've got my indicator in i'm using my adjustable chuck stops and down here i'm checking the actual run out of those make sure that they're still good from their last setting and coming around and checking on each one and then that's going to let me put my part in i just bored the internal contour for the collet and that's it there call it taper relief and then the undersized diameter here that'll get ground in the back for the inch and a quarter of the uh c there's the od contour of the collet nose the actual for the uh larger spindle collet nose we're doing the holes on the face of the actual spindle itself spotting doing the tap drill holes doing the outer rim tap drill holes now we're doing the counter drill holes on those inner and outer these are the spot drill for the cam lock positions this is a regular drill we're going in to do the main metal removal in the hole now it's a flat bottom drill that we're going in to clean up the bottom before we go in with an end mill and do a circular interpolation around there to actually finish the holes off end mill has a corner radius on it to not cause a stress riser now we're spot drilling for the counter board holes that are the where the screws go in that actually hold the spindle together this is the through hole for the for the bolts goes clean through the end cap this is the end cap now not the spindle in the back half of the spindle now we're counter boring with the end mill i need to phase the tapped holes on the far side of this part to be in between the holes that the two drills are in or basically bisecting that line so those two holes are actually one hole off of being on center which bisects that angle i'm just using a tool maker's flat here instead of going over the surface plate so surface plate would do the same thing while that's held in there i'm just using one two three block to temporarily super glue a parallel on in that orientation that will allow me to indicate on this edge when i put it in the chuck gently spin it around till i've got that indicated in true and that will give me my alignment i have the same situation on this one where i've already glued my piece on and same thing where i needed to phase the holes in technically there's no need for the phasing but uh it pays to always if you can't think of a reason why they should be phased it certainly doesn't hurt so the extra little bit of time to phase them means that someday down the road when i decide to bolt something on both sides of this and say oh darn if i didn't only line those two things up this would work i'll think back to this moment say wise decision shop milling the index grooves in and then we'll do a profile cut we're going to remove the material with the chop milling there it's still in the profile and it's indexing its way around it'll be 75 divisions on there and um this will be ground after heat treat so here's that setup with the parallel glued on i've touched in the center and then moved off to each side gently grabbed the chuck and you know tapped it around until i got to run through so as we traverse here we'll see that for a bolt pattern that's plenty close enough and that's just a technique to be able to pick something up on another side that's temporary when you don't have access to it i'm putting the radial holes in the main spindle that are for the eccentric actuating pins so right through here you've got a 3 16 hole 8 inch hole and that supports both ends of the pin where it's eccentric in the middle and that will pull down the the posts that are mounted in the chuck as it goes down so there's the setup i have my six jaw chuck mounted on my harding indexer set just a few details here i've taken my harding indexer and i've milled flats aligned with the spindle so i can grab the vise i've also mounted a plate on the bottom semi-permanently that allows me to grab this vise or the whole setup in the vise sticking vertically so instead of having to take things off the table and t-bolts and all that i can literally just stick this vertically in the vise and grab it doesn't work that well in the bridgeport because it doesn't have enough z travel but over in my dpm i've got a ton of z travel ridiculous amount so i can put this vertically and actually drill things with with plenty of room to spare so when you put a part in something like this there's quite a few alignments that need to take place here number one i have to rotationally phase this pin in to be on center uh just by moving in the chuck jaws i don't have any fine adjust here this is just an index pin style of a neck indexer so i have no means of phasing other than that adjustment i also have to make sure that if it facially runs true in the chuck i have to adjust it this is a buck style you know adjustable chuck set true whatever you want to call it so i have to make sure this runs true and uh then um i i have to pick up center so once i've got this running true diametrically i can sweep this with an indicator and the spindle on both sides just sitting on the tangents here get on center so i know where my zero center is once i have that i can move over put a gauge pin in here which i did and indicate on each side of it by finding the high point both ax vertical position of the probe and rotationally finding the low point on both sides to phase this in and gently tighten the chuck get everything lined up then recheck the facial run out and recheck the tir once that's all set now i'm actually on the axis of this hole and then i'll be able to just index my 12 as i go around putting the features in spot drill on the outside the actual drill for the outer hole reaming the outer hole spotting through down to the bottom of the other side of the hole drilling the bottom side of the hole for the other smaller ream the smaller ream and there's a test fit with the eccentric pin there's a couple of the time saving features i've mentioned before flats on the backing plate so you can grab your chuck backing plates directly in the vise and the adjustable chuck stops uh just makes for a real easy way to get these things in and level and be able to come in and indicate in with the with the indicator to get on zero here we're doing the counter bores in the collet nose starting out with just a straight plunge with an end mill now we're using the same end mill but we're doing a circular interpolation in three steps to open the hole size up then a spot drill down at the bottom to guide the through hole drill that will do right here hard turning a woodruff cutter necked down for clearance here's the setup with the hardened dividing head i have a 17-hole plate on here the sector set for four holes since this is the four to one reduction i have the two degrees tilt of the entire spindle set on the tilt and right now i'm touching off on the top of the chamfer i have dimension on the drawing of how far down i go to get the bottom face of the cutter splitting the center line of the part now we're just milling through each face and it's cutting the opposite face on one side than the other it's kind of confusing because the face of the cutter is right on the center line and here we're tapping in the position of the next part here's a slideshow of the spindle pieces assembled with one two three blocks and plates large 10 inch chuck on the larger spindle then the smaller spindle mounted on the magnetic chuck there's just some examples of things that could be assembled with with the system this is all pre-heat treat testing the parts make sure everything fits and you

Channel: ROBRENZ

Views: 102,644

Keywords:

Id: LUggzM0JOlI

Length: 30min 37sec (1837 seconds)

Published: Tue Oct 20 2020