I did do a search before posting. Couldn't find any threads on it. If this is for real, and if the thrust is adequate, I'm probably a player. If I understand correctly this thing uses a plain shaft for a lead screw. The only one that SmallParts.com stocks is the 3/8" but that's enough for my project. I have no idea what kind of thrust I need. Can you guys check it out and let me know what you think. (I realize it's designed to slip)

You'll need more than 15lbs of thrust. Probably 50-100lbs minimum, for what you want to do. You need a lot of thrust to accelerate quickly to the speeds you want. Sorry, but I don't know the formulas to determine the needed thrust.

ger21]You'll need more than 15lbs of thrust. Probably 50-100lbs minimum, for what you want to do. You need a lot of thrust to accelerate quickly to the speeds you want. Sorry, but I don't know the formulas to determine the needed thrust.

That's okay. You told me what I needed to know. AFter I posted I got to thinking it would probably be difficult to compute how many inches per revolution and such as that. Cool concept though. Maybe later.

Just realized I never did post the pic.

Chunky, here's a thread on that topic.
http://www.cnczone.com/forums/showthread.php?t=3572&highlight=THREADLESS+BALL+SCREW

Chunky, here's a thread on that topic.
http://www.cnczone.com/forums/showthread.php?t=3572&highlight=THREADLESS+BALL+SCREW

I happened to notice a couple of days ago while in the supermarket that this type of 'screw' is used as the mechanism that moves the automatic sliding entrance/exit doors. It's located in the head jamb. One of the doors was being serviced and the access cover had been removed. Perhaps someone in the commercial door repair business would have leads for locating surplus units.

I have seen similar units in work on a large CMM (Coordinate Measuring Machine) that rode on flat air bearings - it worked in that application for slow speed, high precision moves. I don't think it would be applicable to a cutting machine - maybe a plasma or laser, but nothing with erratic, opposing forces to the drive system.

Scott