Ball screw for cross slide and compound

[Silverbullet]

Anybody ever try these on a lathe? Or won't they work because of the dial sizing ? I was just thinking it should work just like on a mill.

 

[hman]

Question is, are you planning to go CNC? If so, ball screws are supposed to be the cat's meow. But if not, I'd be cautious. Because ball screws have a pretty long pitch and low friction, they're easily back-driven. If you installed them, you'd have to be sure to lock any movements not in active use. When set up for CNC, you depend on the holding torque of the "idle" stepper motors.

No, I haven't used ball screws on machine tools myself. That's just some general info I've picked up, in hopes it will be of value to you.

 

[4GSR]

You don't want to do it!

 

[Silverbullet]

Question is, are you planning to go CNC? If so, ball screws are supposed to be the cat's meow. But if not, I'd be cautious. Because ball screws have a pretty long pitch and low friction, they're easily back-driven. If you installed them, you'd have to be sure to lock any movements not in active use. When set up for CNC, you depend on the holding torque of the "idle" stepper
Didn't know that , wouldn't be any good then for normal operations. At least without some kind of snubber to prevent that. I just thought it be better then having backlash on them .

Question is, are you planning to go CNC? If so, ball screws are supposed to be the cat's meow. But if not, I'd be cautious. Because ball screws have a pretty long pitch and low friction, they're easily back-driven. If you installed them, you'd have to be sure to lock any movements not in active use. When set up for CNC, you depend on the holding torque of the "idle" stepper motors.

No, I haven't used ball screws on machine tools myself. That's just some general info I've picked up, in hopes it will be of value to you.

I didn't know they were like that , wouldn't make sense to use them unless there's away to add a snubber so they can't coast free. I was just thinking if I rebuilt my cross slide with them instead of the brass nut system they came with. Unless I use a double or split take up. My old machines never been changed so I was thinking why not.

 

[darkzero]

Yep, like hman stated, too low of friction. No reason to use ball screws unless converting to CNC. That's why you never see them on manual machines.

 

[4GSR]

I worked on a special machine tool project in my much younger years. We put a Duff-Norton ball screw jactuator on top of the column of a large mill to raise and lower the 5,000 lb slide that held the vertical spindle and 50 HP motor. Worked beautiful raising it and lowering it. Stopped for lunch, break, I don't remember, came back and the vertical slide was at the bottom of the stroke. As said, the very low friction of the ball screw will not provide the braking needed to keep it from creeping. To fix the problem, we put a C-H fail safe electric brake on the input shaft of the jacuator. It had double shafts so you could put the motor on either side of the unit. Really think the extra shaft was for a brake. This was before the days of putting stepping motors on something like this. They were available at $5K a pop, plus the cost of a controller, $10K plus back then.