Rich Amaral wrote: > Hey guys, > > This is purely a machining question. > > I'm currently retrofitting the lead screws on my home built cnc router > with ACME thread screws. Yes, I run EMC2. The screws are about 3 feet > long by 3/8 in and need to be turned a bit at either end to fit the > stepper motor coupling and bearing (at the other end). > > I have a Craftsman professional lathe (much like an Atlas) in decent > shape. After turning both ends to size, I discovered the screw became > warped (about 37 thousandths, a noticeable amount). I don't think the > screw was warped before, although I'm not 100% sure. That leaves me > and the way I held the screw in the lathe (I think). > > I held the screw by wrapping some copper around the threads and > clamping that portion in the chuck, leaving the remainder of the screw > sticking out the left side of the lathe. The screw wobbled a bit but > nothing that looked too bad, at least to me. Could this have warped > the screw?
Hard to say - depends on how fast it was turning, among other things. As an aside - long thin things sticking out the left end of the lathe can be VERY BAD. Above a critical speed (which isn't necessarily that fast), centrifugal force can make the part abruptly turn into a giant L, and the end whipping around can smash the hell out of anything nearby, including you. > More importantly, how should the screw be held in the lathe to prevent > warping or other damage during machining? Thanks! One step to take would be to turn and bore a bushing that fits nicely into the left end of the spindle, and holds the screw centered at that end. Regards, John Kasunich ------------------------------------------------------------------------------ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
