> -----Original Message----- > From: Gregg Eshelman via Emc-users [mailto:emc- > Something to try for a loose spline drive is make a fixture to hold the splined > shaft and sleeve concentric so there's an even gap all around between the two > and sealed at the bottom end so nothing can leak out. > > The bore should be degreased and roughened by bead or sand blasting. The > splined shaft will need to be uniformly straight and smooth, then have mold > release applied, missing nowhere. I'd apply a couple of coats of TR-104 High > Temp Mold release wax then spray on the release for whatever resin will be > used to fill the gap. > > Injecting Moglice into the gap should work the best. That stuff is extremely > hard and really bonds to iron and steel. I've used it to repair worn half nuts on > metal lathes by clamping them to the far right end of the leadscrew to mold > the resin to shape. How hard is it? It took quite a bit of effort to grind off the > excess squeezed out Moglice with a grindstone in a Dremel. > > Epoxy or hard urethane with some graphite or PTFE powder mixed in might > work too. Smooth-On has a bonding agent they call Ure-Bond that makes their > resins and rubbers stick very well to metals. > > Might need a press to pop the shaft free, but the result should be a nearly zero > clearance sliding fit that's not going to rattle. If the mold release does its job > right, a soft face mallet ought to pop it loose. > > Another possibility would be DIY broaching a splined sleeve that's a much > better fit, boring the pulley out to press the sleeve in, then touching up the > splines if the sleeve compressed enough to make it too tight a fit. > > If Delrin or Acetal can be melted and injected in, that could make a zero > clearance lining. It would need to be able to flow out on both ends to form a > flange to keep it from sliding out of the bore. > > If it's a really large gap, make a brass or bronze sleeve to fit the splines on the > shaft and pulley. Or perhaps just some strips laid into the grooves on the shaft, > the pulley slid on, then the ends of the strips bent over and soldered to > washers would take up the slack. >
It's kind of a strange setup. There's the quill with the splined shaft and I don't want to lose that mechanical feature for manual operation. But the pulley isn't directly keyed. Instead there's a tapered hub with the splines. And then the pulley sits on that and is held down with a nut and starred key washer with a tab in one of the spline slots. The up side of this is that I can create different pulleys and I don't have to make a new internal spline. I have a tapered hub now that I can hold between centers. Although in hindsight I should have used a larger diameter shaft for this hub. The motor pulley was also a casting. https://www.autoartisans.com/mill/NewPulleys-1.jpg The original pulley was mounted in the 4 jaw and centered. Then the taper picked off from that. And finally between centers a mounting code made. https://www.autoartisans.com/mill/Arbour-2.jpg The original pulley was put on that to verify that there was no runout. Then casting the pulley from a 3D printed pattern. https://www.autoartisans.com/mill/SpindlePulleyRawCasting.jpg And machining it after turning the internal taper. https://www.autoartisans.com/mill/TurningPulley-2.jpg And finally an encoder disk. https://www.autoartisans.com/mill/MountedEncoderDisk.jpg
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