On Thursday, January 27, 2022 2:57:21 AM EST Roland Jollivet wrote: > On Thu, 27 Jan 2022 at 06:49, Ralph Stirling > <[email protected]> > wrote: > > I had some problems today with a small XL timing > > pulley slipping on a NEMA17 stepper shaft due to > > the set screw loosening after running for long > > periods (multiple days). I drilled and tapped a > > second set screw hole, and I can probably apply > > some thread locker, but I got to wondering if it > > would be possible to make a miniature taper lock > > type bushing and pulley to clamp onto a stepper > > shaft. Anybody ever seen anything like that? > > > > The original taper lock system has a split bushing > > with an 8 degree taper against the pulley. They > > also have a clever set screw arrangement to tighten > > the pieces together and to jack them apart when > > removing. If you haven't used them before, a video > > is the best way to understand them: > > https://www.youtube.com/watch?v=-3K_vf_7fhM > > > > I like to 3d print my timing pulley perimeters, but > > a metal hub is nice (as has been discussed on here > > in the past). I'm pondering how I could make hybrid > > pulleys with a taper locking hub. Threading the holes > > in the plastic pulley wouldn't work so well. Perhaps > > some threaded metal insert can be incorporated from > > the back side. > > > > Enough of my musings. Looking forward to hearing > > other ideas and suggestions. > > > > -- Ralph > > If you're 3D printing a larger pulley, you could do something as in the > pic. You drive a self-tapper into the small hole on the left to clamp > the flexure. > Add more screws/holes as needed. > > Roland Attached if it passes, is a piece of the openscad screen show that armature as its printed right now. The reduced diameter extension projects out of the back of the housing to engage as much of the 8mm motor shaft as possible. Unshown on the bottom is a pocket for another metal bearing that is optional. If its installed at about $1.75 additional cost, a printed peg is inserted thru the 53 tooth output pulley center hole to engage the 10mm bore of that bearing to help brace that end of the armature, and that is in the one running on the kitchen counter, but is not doing enough to warrant its continued use and additional cost. Everytime I print another of this part, I reduce the diameter of the hole another .01mm which should hold it a bit closer to centered. The hole sounds oversized, but remember the nozzle is .4mm, meaning its lying down plastic at 8.35mm whose half the nozzle diameter smaller for the inside measurement or around 7.97mm, so it is a drive with a small hammer fit the first time installed on the motor shaft. Accuracy and a 3d print do not really belong in the same paragraph. :o)
Cheers, Gene Heskett. -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author, 1940) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis Genes Web page <http://geneslinuxbox.net:6309/gene>
_______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
