I've seen CAD models of the complete Bridgeport machine on GrabCad. It really is helpful to have a good model so you can test-fit parts before you make them.
I found a model of my Harbor Fright minimill so now I can able to make add-on parts that match the screw-holes on the mill, first try. Yes I had the verify the model. I would not trust something I downloaded. I know what you said about dropping the z-axis faster than gravity allows. I'm using a ball screw for that. Turns out the Chinese ball screws are cheap and actually better than spec'd. On Sat, Jan 2, 2021 at 10:38 AM John Dammeyer <[email protected]> wrote: > > > > From: Gene Heskett [mailto:[email protected]] > > > I have noticed the 3D > > > printed pulleys are noisier than the metal ones. But the noisy grind > > > of the stepper motor is also gone. > > > > That's also worthwhile. I've also found the downloadable pulley making > > code, like from thingiverse, generates pretty sloppy pulleys. Bound to > > be noisy when the tooth fill is only 25%. But I don't know how to fix > > the src code for those parametric composers. So after about 6 passes at > > making pulleys, I ordered alu ones. > > I have XML pulleys on the XY axis but those are 1.27NM motors. The Knee > has a 3.5NM because that's what the 7.5NM Stepper motor dropped to at 300 > RPM when it would skip steps. Especially with the bigger heavier vise and > Rotary table. > > But the L type pulleys and belt were a gift from a friend so that's what I > used. The issue I ran into because I didn't do my homework before I > ordered the motor was the shaft diameter of 19mm (roughly 3/4"). > > The 12T pulley is just too small to also have a key and enough 'meat' for > the pulley teeth. As it was I pivoted the key slot by 6 degrees from the > imported STEP drawing so if I ran a set screw through the tooth there's bee > enough material for threads. Anchoring the key from the tooth slot didn't > create enough material. See attached photo. > > Fine if there's room for a larger diameter hub. Unfortunately I had to > scrap that design because the belt didn't line up. Couldn't move the motor > back. Couldn't move the upper pulley forward. Had to redesign with a 15T > pulley so I can get a set screw through the tooth crest. > > John > > > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > -- Chris Albertson Redondo Beach, California _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
