[DerekZahn]

Hi all,

I'm such an addict... . Yesterday I came across theseball screws on Surplus Center and of course was unable to resist ordering a couple pairs, with the idea of probably doubling up the nuts on one screw to reduce backlash, and if necessary then using ball screw mapping in Mach3 to compensate for lead errors. But all that does require a certain level of quality from the units to start with...

Anybody check these out yet? Of course, the ends will have to be machined and Yadda Yadda Yadda ... But who can resist $15 for a pair of ball screws?

[RICHARD ZASTROW]

ACME screws with ball travelling blocks?

Dick Z

[DerekZahn]

ACME screws with ball travelling blocks?

I think the person writing the catalog copy just isn't that familiar with the terminology... the close-up picture here looks like a rolled ball screw to me...

At any rate, I'll report back once I receive them.

[doorknob]

I know that several members here have bought those ball screws (and in fact I have been contemplating buying two or perhaps four of them, too), but I don't think that I've seen any "after action reports" from anyone who has actually used them in a project.

So, please keep us posted on your findings...

[louieatienza]

They sell a bunch of these on eBay... can't say for their quality however...

[palenn]

I would guess that these ballscrews are designed for farm machinery tongue jacks. The square flange probably welds to part of the jack assembly. The jacks use telescoping square tubing.

[keebler303]

Ballscrews aren't used for tongue jacks as they would have a tendency to back drive. They may well be much less precise than "cnc quality" though.

Matt

[palenn]

ATWOOD Manual Ball Screw Camper Jacks (4-Pack) #84371
I wondered about the backdriving also. Apparently some sort of locking device and/or worm drive is used?

[keebler303]

Yeah, those look like they are worm drive. So maybe they do use ballscrews in tongue jacks.

Matt

[DerekZahn]

Well I got those ballscrews... They aren't complete junk but they do have a bit of slop. Maybe they are part of a jack or something; seems to me that they are designed for power transmission more than positioning. It might be worth a try to double up the nuts to get rid of backlash, but the nuts are 3" long each so that would only leave about 8" of travel, and I suspect they won't run very smoothly in that configuration. They just don't have the "feel" of a precision device... More work than it's worth, most likely.

And they are covered in smelly red grease.