[tc429]

pic of the little 4th I put on my bridgeport- its a wrist actuator off a old fanuc S-110R robot- we scrapped a dozen of them yrs ago, I talked my boss out of a couple knuckle drives- they had a chain sprocket output- incredibly, the OD of the sprocket is exactly the ID of a Shars 3" chuck (like 50 bucks on ebay).

punched out a old rt angle plate for a mount, turned up a clamp collar to pinch the gear teeth against the chuck, voila! no measurable backlash(harmonic drive) or runout, decent bearings...those robots used the 'R-C' thru 'R-G' analog controllers, for 6047 DC (yellow cap- black in this case) or 6050 AC(red cap) motors...just thought I'd put this up if anyones contemplating a small 4th.

eventually I'll make a heavier mount with keys and whatnot, but for now, it works

[Shanghyd]

Awesome 4th axis. I'm looking for one but for my little mini mill that runs on Mach3.