MAKING LINEAR BALL WAY CAGES

hello I'm Robin welcome to my shop today we are going to look at making linear ball cages for my Mitsui surface grinder rebuild these are the x-axis the long table travel balls that this table sits on these ride in hardened d2v way and flat way rails that are bolted into the castings and in the back here we have the old cages and we'll take a look at those as we get zoomed in here and these cages were very simplistic I believe they were acrylic plastic and they brittle very few screw holes and just a very simple chamfer and a straight bore for how the the sit on the ball this had a tendency to squeegee off and scrape off the lubrication that we can see here and just not an ideal situation so we're going to show how I redesigned these added a few changes and some of them are going from acrylic to a Delrin material more screws more smaller screws or more uniform hold and some features on how we are trying to get oil in here going from 27 balls in the original rail to 30 balls in the new rail so we're gaining three three balls more than 27 whatever percent that works out to we're getting that much more bearing capacity for the same loading stress on the on the balls and the races so a little bit stiffer and we'll tear into how we designed these and how we machined them I don't think those cages were necessarily original in that soui they don't really look like a very high quality design or execution but my main reason for making the cages other than the fact that they were broken in and I need to make new ones anyhow was to move from grease lubrication which is what they recommended with a three month interval of taking the table off and cleaning the grease out putting fresh grease in which is totally impractical to an oil level system where I'm going to fill the saddle put a sight glass in a philosophical where it just touches the bottom of the balls enough that the as the balls roll they'll carry oil up into the wick section that I've got built into the cage and the wick will carry the oil around to all all edges or all sides of the ball to lubricate the 45-degree section also so you'll see that design aspect in the upcoming section here I've modeled my piece which is 23 inches long by an inch high extruded it 1/8 of an inch thick and then I'm going to add the fill it's on the corner I could have done this in the sketch also but now we're going to come in and do the actual design of the ball so we're gonna switch our view here and look at the sketch of this so i modeled the ball the 5/8 ball my spacing off the end out of the center of the ball on the bottom edge and what i'm doing here is i'm looking at the cross-section that i want to cut in this by revolving it around the center line of the ball here so that i get the actual pocket contours that I'm after I need something to sit on the ball itself so what I've done is I've put a point on the ball in line with this edge and set a 10 thousandths cap for ending up with a twenty thousand play up and down on the ball to be in there this gap is 10 thousandths is to make sure that the oil that comes up through doesn't get squeegeed off by this edge and then this pocket is to hold the felt which is what my originally was thinking of putting in place there too wet the entire circumference of the ball regardless of where the oil got carried in so that's the cross-section just the power of using a sketch using points to establish the design that you're after so main thing here was to have some clearance this that this will actually sit on the ball this corner and use my gravity this will pull down and obviously there's two halves of this I'm just modeling the top half and the bottom half is the same thing symmetrical mirror image of it and that will captivate the ball keep it from from falling out there's a section view of what that contour looks like in the part and now I'm going to turn that off and we're going to look at that from the bottom and you can see what that pocket looks like but now we're going to turn on the the actual contour this is where we designed to make sure that we weren't squeezing off oil where it where it needed to go I'm going to look at the sketch that I did there and there I say okay I need this zone to be open this is going to get a cut here to allow the will to come up on but I need an oil clearance where the 45 degrees sides would hit so I thought well if I do one here at 45 degrees and model the pocket cut out and then I could just rotate that around so that's what I did this was just to understand the spacing to get things where I wanted it so now we'll do that cut will slide down and activate the circular pattern and now you can see it at both ends here whichever way we're rolling oil can come up through this gap and but the wick the felt which what I was really thinking what's going to use would carry this oil around and keep everything wet over here to the 45 degree point on both locations and the sides obviously which wouldn't function anyhow but that's the whole idea and then these edges right here or the only part that actually touches the ball and it doesn't touch where the actual paths of of the oil should be then we linear pattern that down the whole strip and we add our screw holes strategically in there and we've got our design so here I've done just enough of a drawing to get the dimensions that I actually need for doing the milling and drilling of this piece so it's not a drawing that you would actually send out somewhere to get manufactured I just need the key features for me to be able to do the programming so relatively simplistic and just has the bare essentials this is my block of wood that I intend to use clamped in devices as my base and I'm going to fly cut it off and this is the black Delrin that the cages are going to be made from and what I'm checking here is I have three different transfer adhesives that are just that he's that there's no liner my favorite 467 MP which works great 99% of time very high bond I'm not sure exactly which one this is f9 460 PC that one I mean my opinion doesn't work as good as this one this one is specifically for plastics hard to adhere plastics and it does actually work really well like polyethylene and things that typically things don't stick to this stuff's really good I'm going to test these three pieces with a piece of each of these tapes to see which one gives me the best bond to hold these while I mill the the contours my three samples here I have pressed them firmly against the wood for a couple minutes and the vise I won't be having that situation when on the mill but for testing purposes to make this consistent I pressed them on hard to get the adhesive a chance to bond most likely the wood is going to be the weak link on this for multitude reasons whatever with natural oil contents in the wood or you name it so testing wise if I lift it on this because the strip is from here to here the actual adhesive strip there's it's only a half-inch wide if I lifted here I'd be doing a peel test more or less because the the Flex and the material the plastic would Bend and slowly pull here and start this edge and peel across by pushing down on this instead since I have a fulcrum that's relatively far away from the centerline of the adhesive I'm going to get more of a tensile test of the glue which might be more representative I'm going to put my impression gauge or my force gauge in peak mode so it'll capture the peak and I'm just going to press down on this gently holding giving it a little time to react because as we know these things fail kind of progressively I'm just going to keep putting pressure on and the peak mode should record it might help if I turn the camera where you can see it yes that's me quivering trying to push hard enough help notice the that's that's my force gauge saying oh that's all I can't and that we maxed it out on that okay zero and we're gonna try the second one okay 384 ounces that's the very high bond tape and it looks like the yes the the adhesion to the plastic is what failed so we're going to zero that out I'll come to the plastic bond tape three-fifty okay like like I said before this 467 MP seems to be the winner most of the time so that's what I'm going to use and obviously for what I'm doing with a little eighth inch o flute super sharp end mill cutting around these things this is all overkill but going to use the 467 MP I'm going to apply the transfer tape to the plastic first and I'm only going to put it for this 3/16 of an inch on either side here I'm concerned that if I put full-face tape down here that as the cutter goes through here that it's going to get a buildup of that he's up on the tip of the cutter and just caused a mess and I don't think the forces are going to be that high that we're gonna have any issues with just using the the two pieces it'll make it easier to clean up also but one of the things that's important in doing that is this Solid Edge has some burrs that aren't huge but they're probably enough to make the tape not bond as well as it could as far as laying down flat on the on the wood so I'm taking a ceramic Noga scraper just settling that edge all the way around before I put the tape on so thinking about how I could get this tape on here only 3/16 wide I said myself if I space the pieces apart I have 1/2 inch wide tape I want 3/16 on each side that's 3/8 for the two of them leaving 1/8 put 1/8 inch now between these two put them together and then just take the tape and we'll have all Center it as I go down the route here like this I'll put this on and just visually brightest in synergy I think anything in the ballpark is going to be good enough he's trying to use my head here to make this go easier now that that's on there garnish this on so I know I've got a good adhesion here and I'll just take a blade and I'll get rid of my Dell pin so I don't run into them they're stuck to the tape there we go put this back down now and then just ride the edge and part cutting the exodus table [Music] where this away there we have it there's our two edges and we'll just treat places like this and do it again gluing the strip down on the wood drilling holes for the tapped holes and the counter sunk holes milling the periphery doing the pockets with the cutouts and they release for the oil passage and working our way down through there with clamps and then finally peeling the strip off at the end and getting ready to put another one on so it turns out that I finished the ball cages the 30 ball ball cages complete using the wood strip and everything was fine and as I'm posting on Instagram about making the cages in the process of reading the comment I have this thought wait a minute this is a video on V contact versus Avilan flat and there's a distinct possibility that the number of balls should be different in those two cages to have the same deflection characteristics so I mentioned that in the comment and then go and start doing some calculations and after the third attempt I finally get the calculation correct with some help of a Instagram friend that commented that I was doing part of the calculation wrong and making a initial blunder on my own that I caught so third time was a charm and I'm just going to show us a rough idea of what calculations are involved and then we're going to carry along where I realized okay I've got to make two more cages there are two more pieces which is one cage for a different number of balls and I have a bunch of linear needle bearing cages I need to make for the vertical slide of the Mitsui so I need to make a better system for holding the students stuff and doing the cage like items like this a better clamping system better way of doing it in general than a piece of wood stuck in the vise so I'm going to show you now the rough calculations and then the rest of the video is going to carry on with making the clamping system and then showing the actual similar procedures same procedures I used for the wooden version except with the nicer newer clamping system so the table configuration that we have is 90 degree V's hardened 90 degree B's in the saddle it has two V's the table top has a V and a flat they ride on these five eighths diameter balls and that's what the cages are forward to hold these in position this is what jumped to mind as I was doing the Instagram post saying wait a minute it could be that the ball since the deflection characteristics of this under load may be different it may be that to make it be the same you need a different number of balls and the rails so what this boils down to is when you there are calculations called Hertzian stress calculations and as part of those is like when you press the ball onto a flat plane or a ball on a ball or a cylinder on a plane all those things have a calculations they're not really complicated you just not have to have your eyes glaze over and just do your pretty generic math to calculate them it's very handy to to know and in this particular case let's just take the flat on the ball that's the generic calculation so you take whatever the load is that you're gonna have one there and there's a calculation that says for to pick the center of the ball you put a certain amount of load on this plate how much is is this going to compress how much is the ball going to deform into the plate the ball is going to compress some what's the approach the normal approach of the center of the ball relative to the plane with that calculation mind we have a different situation here where when you have the ball hitting on two sides and in the vertical force first of all you have to split the force in half because you have two places resisting it and then you have to convert the vertical force into the normal force and once you have that then you get that normal approach meaning how much more does how much closer does the ball get to this plane in this direction and that was where I was making a mistake my second time it turns out that it's the in this case cosine divided by the cosine of 45 degrees gives you the actual vertical approach all that basically is if we load this situation doing all those calculations for a given weight how much does this move these two move together same weight how much do these moves whatever that difference is we adjust the number of balls such that the total weight per ball increases or decreases whatever is necessary to get the total deflection of these two systems the same for the same loading well it turns out that dropping to twenty-seven balls on the V on V versus the thirty balls on the view on flat gives us a uniform deflection under load so that's why we're returning around and making the twenty-seven ball cages to make everything work out properly and we're talking you know getting down into the to the you know five ten millions or less variations here that we want this to be predictable and how it behaves making up some new clamps these on the left are Harbor Freight which are pretty darn nice and these are vice-grip they're almost identical and what I'm doing here is I'm going to be grinding the jog pattern off of here I'm gonna be putting radius feet on the ends I'm grinding the inside of the jaws smooth here just wanted you to know this one technique is you'll see as I'm pulling across there I'm keeping an even spark pattern across almost the whole face of the belt so that the belt is being used all the way across even though I'm traversing with a slight angle to it before after and you'll see why I want the thinner section when you see these in use I'm burning off and Radia Singh with the file these pieces of half-inch diameter if I count 44 that will become the jaw pieces that little stop set up there with the collet it's very handy for this type of thing surface ground these not because they need to be precise if I matching the widths I'll be able to grab these in the vise together and do a group of them in one one-shot otherwise they would wouldn't tighten up evenly if they're not all the same thickness now with them all the same thickness I am able to mill them as a group and down to thickness now I'm milling a slot that is just a little bit wider than the jaw that will keep these jaw pieces centered as I weld them to the tips of the pliers I'm using an end mill that's a little bit smaller than necessary and then stepping over or sideways using the digital on both of the slots there's two pieces side by side shown there here we're milling the semicircle in half again leaving the quarter segment we're after I'm using a 180 grit abrasive nylon brush 6 inch diameter to deeper all those milled edges just to knock the the sharpness off these do a really nice job really handy to have around a fine grit when the I think 320 range is also handy but the 180 really removes the burrs nicely and through the magic of video all those tips are welded ordered and radiused and ready to go so what on earth would 3m strip call have to do with clamping well this stuff is basically industrial snot it's sticky as all get-out and stays sticky unless you do something oily with it so I have these pressure pads on here to distribute the force of the clamps over the plastic and when it's some way that I didn't have to fumble around with holding the pad placing it so I could move these around quickly as we're milling our way along and I thought of water that on there would work well because it's flexible yet holds it in place and sure enough that's what it does so it's pretty handy stuff around have around works well for stopping leaks in you know coolant situations and creases and doors and whatever where you need to put some sealant that stays put but it is still removable drilling starter holes for the square holes and then we're milling the whole square to the actual 3/4 size so that the broach will only have to remove the 5/32 radius that's left in the corner from using a 5/16 ml and part of that is so that the broach can actually fit in and be aligned rotationally square with the piece but also because the broach is too long for my horrible breath one of the reasons I had to mill the rectangular hole instead of using the pilot that would be for this number one the pilot is bigger than the square it's thirteen sixteenths pilot for a three-quarter broach and this broach is too long for the throat height of this this arbor press so by milling the the square a little bit bigger than the final size it lets the broach drop in far enough to be able to use this press I'm gonna be 40 on there and that that went that far because the all this is really taking out is the 5/32 corner radius the left end mill left now we're getting a view of why this is nice and universal because we have a virtually undisturbed clamping ledge full length to be able to grab ports and because of the holes we put in the back we can also pop through and grab from the other side if we need to leave one side of it so these clamps you can see why the the design of those clamps are such that they can reach in and grab full distance and that's that's why I designed like that they can open up to two inches but that's probably going to be pretty where rare most of the stuff I'm gonna do in here is going to be relatively thin here's the sacrificial strip that I'm putting on top of the fixture its sixteenth thick abs hair cell finish that's that that finish there and that finishes at first I thought oh that's a stupid finish and then I made some vacuform parts and realized that that finish is awesome because it regardless of scratches and things it leaves a nice-looking part so on the back I have attached I'm going to attach this to the aluminum semi-permanently with the 467 MP still my favorite all-around transfer adhesive and that's going to stick down and this is so that I can drill through my actual pieces my eighth inch thick Delrin pieces and without going into my aluminum plate I don't want this thing I'll pepper with holes unless it's absolutely necessary so this is going to the two strips on the outside here showed that previously on the wooden fixture how I put those on side by side these are gonna hold down for the drilling and for the milling around the outside it was some a clamp assist as we go around one thing it's very important with transfer tapes or any tape is to really burnish it down to get the intimate contact these tapes some tapes one yeah you look at the specs require a certain amount of psi for a certain period of time before the actual adhesive strength actually takes place so just throw in these on give it a quick rub with your finger is not the same thing as putting it on furnishing it firmly so that all the air bubbles they're out and it's intimately in contact with the park is pretty important it's a fixture in place I have my sacrificial strip with my transfer tape on the back I have dowel holes in here that are used for just aligning these strips I have this currently what I'm working on these pieces are basically going to be about an inch wide so I'm centering that to put some reference down pin holes in the back one on the end such as we put repetitive pieces and we can repeat the position so I'm going to transfer tape down this sacrificial strip and use the dowel holes to to support that so I'm going to take off the backing strip backing paper I have already previously cleaned this with alcohol very well and I'm gonna make sure I get up against my stops first my reference piece is there and get that down and I have parallels already sitting here that I'm going to use to clamp this to get this the bond real well and using my my special modified pliers here these saw me modifying the vise grips and in this case some seven of these are hazard fraught pliers and this is to really get that teeth to bond well I don't want the sacrificial strip to move or lift up when I peel the other ones okay look that's a little bit get some get some adhesion now that the strip is bonded down the sacrificial strip I'm decreasing the top of it because now I'm going to put down the delver in the actual part material on top of this with that has the roughly three sixteenths quarter inch wide strips down each side so we're going to do the exact same thing again except with the part material and as you can see here we have the two the two strips it's going to go facedown and that's just going to hold it on the sides while we do the periphery and the holes will do without anything holding it down the periphery will do by holding it on the sides with the clamps in for either edge you'll go around partway pause and then swip flip the clamps over the other side and go down the other side so now the same procedure here let's be careful to get the corner started properly get up against this pin so I'm not warping my plastic as I push down getting in alongside and pressing down now I'll put those same clamps back your strips back on same parallels and we'll put the clamps back on and clamp this clamp this tight again to get the get this to bond on the Delrin to the sacrificial strip adhesion we're milling the outside periphery of the whole part and I'm moving the clamps as the cutter gets past each section and I'm taking the cutter from the back or the clamps from the back to the front and just following around and then obviously once they're all moved the can run down the back undisturbed and you could see why was important to have those pads captive with the flexible material now I'm doing the same technique we're we're milling the holes and the contours in the pockets by transferring the clamps as we go just getting them out of the way in time and working our way down the hole the whole piece it's going relatively slow it's not really not like a panicky thing you could always hit feed hold to to move the clamps if necessary and we're at the end and now we're drilling the holes without any clamping whatsoever because there's hardly any loads on this and that doesn't require much force just using air to get the chips from tangling on the drill so we we don't want to put stress on the tape that's holding this down to the plate now we're going to come up to this end I'm going to start under here and slide up right under this and this way I'm not stressing the either of the plastics and there we are we're ready to go and just rub off the adhesive there's what it looks like here at the optical comparator I have my 256 tab in here and the reason I have it in here is I'm measuring the root diameter of the tap so I've got my one root lined up with my cross here I have my vertical indicator zero and now I'm going to move to this one see what the line is there come down to my indicator here those 61 four so sixty one and a half thousand diameter drill would be a hundred percent thread so a sixteenth drill will be fine and the reason that I'm doing this is this is Delrin and in plastics there's no reason not to use 100 percent thread the only reason we use less than a percent in other materials is that the twork to drive the tap in steals and aluminum's and things goes up dramatically and there's not a huge increase in strength from 75 percent to 100 percent thread in the plastic I think it will help a little bit and that's the reason I'm doing it I'm using my floating torque tapping head it's as adjustable torque but I'm not using the torque here at all I'm just using it for the floating aspect because this flexibility here will keep from ripping the threads out I tried the rigid tap this with the bridge port which would be a common thing to do the strength of the it'd be very easy to just pull the threads out just from not following the lead so I'm using this purely for this float aspect slide down to the next location line up lather rinse repeat [Music] Horo steel wool is the ideal deburring medium for this remember we don't want to have any embedded brace of grit in these cages that would transfer to the or scratch the grade 10 balls so that's why this is ideal doesn't leave any abrasive residue works good on any crispy plastic like Delrin PBT things like that not not the best on super soft stuff like Teflon point here's our hundred pour per inch reticulated foam and what I'm looking for now is I'm taking my calipers and gently squeezing this until it gives me some resistance to see what it's compressed tight this without killing it you know smashing it to death the response so 15,000th is a good number that's how deep I'm going to make my my cut lips on my die so that it presses it the whole thing flat in the process and then the pieces will just jump right out of there so that's an important number to know if I made it shallower than that it would prompt might damage the foam and permanently impaired it and I might actually make it 20 just to be safe so here's the thigh that I've made to cut this reticulated foam ring of very very small cross-section for the five eighths ID point seven oh five oh D so it's very small cross-section wall thickness and I'll show video of me actually machining this this was a just a pre hardened this was a test puck actually from a heat-treat batch where I send a puck and say heat treat on the puck only so you don't end up with diamond indentations on your pieces so that's that's where this piece came from so it's already hardened and I just hard turn the features of this so my tool is into the 20,000th depth position from after facing it off now I'm going to touch that known diameter that diameter I've hard turned and I know it's point nine eight nine so I'm actually going to go in and I'm I'm using the camera to see what I'm doing and I'm going to touch but I just just see some fuzz from the from the corner there [Music] I'm actually watching right through the camera because it's the best view I've got right there I just touched okay I'm gonna shut it off and right now I'm going to set my ex for that tool 37 at point nine eight nine now what that means is that that 20,000 step wherever I go the intersection of that front angle that's touching now and the face is going to be that diameter so that's going to let me establish the Odie's of my cutting lip and right now I'm going to go in and actually cut those two sighs the Odie's because for odie work I have my tool a little below center because it prefers that before I go and do the I D side I'm going to get up a little bow Center because the tool prefers to be above Center on the IDs so that's why I'm doing the two Odie's first so now I'm going to set my digital at X point seven zero five because that's the OD of the foam ring that I want so I'm going to go ahead and cut right now I'm just going to gently cut this [Music] you can write in till I get to my [Music] we try to get them here focus a little bit better in there we go [Music] one thing I see people doing let's say they're wrong but you don't need to have red chips when you're cutting with CBN tools I typically run a lot slower and surface footages than that contains less quite long time so there's the one I just went to my diner and I'm pulling out okay now I'm going to set the next inner diameter which is going to be 0.625 [Music] right and that is not very for different and I'm going to actually set that and then I'm just going to plunge in on on Z [Music] right here [Music] and plunge into my death and I'll have that inside correct right there that's the space thing that's how skinny that is on the face now I'm going to raise a little bit on Center height just a trifle come in and touch on this known ID with the other side of the tool and the tool here in view I'm going to touch with this side of the tool now on the ID of this hole here right there on this ID which is known that's point 310 I'll go into my 20,000 step and I'll come in until I just see chips on that set my digital for what the idea is now because I've done both Odie's so first I'm going to Jack my Center head up a little bit here just gonna loosen up and give this a little twist now I'm ready to go okay now I'm in at my 20,000 step and now I'm going to come in I'm gonna touch you in the ID until I just get some chips on that edge now I'm just very carefully gonna come in and touch here until I just see right there now I'm gonna turn off I'm gonna set my X at my point 310 I think I might have cut just a little bit there so I'm going to make it 311 all right now in setting my digital to go to my same diameter in this case point six two five six two five X point six two five and my Z is point O two and we're going to turn on and now we're going to cut them up cut out until we [Music] the chips are way years and she's gone only see but now I'm going to set my 7:05 my X point seven two five and I'm coming into the other side of the the one that I did on the first Odie's I turned 705 I'm going to plunge into that to generate the outer go into my death and I've got those two edges but now this is 3m strip caulk that I have on here just to hold this I have a little pilot hole in the back of this to keep it centered on the dowel pin and that's it that it puts even pressure and this piece can actually just move tilt to Center on the plate and have a uniform pressure part of what makes this work is compressing the foam all the way down first before it cuts those those pieces are the ribs are only about 20,000 s high and that's just about the compress height of the foam where it's it does want to be compressed any further so simple as that works really nicely you now I'm getting ready to load the particulated foam wicks into the actual seats where they go and I'm going to load them first and let the ball scoot down into the to the hole so I'll just march along and put all these in and I'll be back now I'm taking the five eighths diameter grade ten ball dropping it in I'm putting Velo site ten now on these and you can see the reticulated foam wicking the oil all the way around the it actually looks dirty it looks what you're seeing the black come through the oil and I'm actually amazed at how much oil they these actually hold takes quite a bit of oil to saturate this so I think they're going to work really nicely here you can see the recess for the foam ring and then the little individual lips that leave room for the oil to smear on the cut the two contact areas either the flat on the bottom or the 45 degree contact now I'm going to very carefully attempt to line this up and jiggle this in place and it just falls right on oh that's one of the reasons why I felt was several reasons why the felt was was no good and there we have a completed cage this is the thirty ball cage excuse me this is a twenty-seven ball cage and we'll be putting the thirty ball cage together next these are getting bagged up to stay clean till assembly time I hope you found something useful or educational in this and I'll be back

Channel: ROBRENZ

Views: 109,002

Rating: 4.9277506 out of 5

Keywords: mitsui, surface grinder, ball way, toolmaking, rebuilding, machine rebuilding

Id: OrFG8X7w8yQ

Length: 50min 21sec (3021 seconds)

Published: Tue Aug 14 2018