x axis slop

[Tree]

I'm wondering how much slop on the x axis crank of a bridgeport is normal. The one in our shop freely turns about 180 degrees between travel to left and right. This is certainly annoying but is it to be expected? I must confess that I have not looked in the manual(if we have one) to see if there is a simple adjustment to tighten this up. The situation occurs anywhere along the length of the x axis. The machine is a 20 to 30 year old (I'm guessing) bridgeport with variable speed head. The x axis has an aftermarket add-on drive attached to the right hand end. Thanks in advance for your input.

[Randy]

Yikes! .100" of backlash sounds excessive to me. My b-port clone has less than .020 on both axes, and I bought it used ten years ago and don't recall if I've ever adjusted the lead nuts. Of course I don't use it hours every day. I think the machines at work have maybe .040 max. Some backlash can be adjusted out. The lead nuts either are or can be spilt in two, and the two halves drawn together with an adjustment screw. The left half will take up the load when you move the table to the right and vice versa. But with that much wear I'd replace the nut if I had any say in the matter.

[halfnut]

Thought this was normal, almost. People sometimes get all worked up about backlash, unduly so, as long as the nut doesn't strip out it will work just fine. But.

Got a power feed unit added, check out and make sure there is no end play in leadscrew, something might be loose, not shouldered up right. Never had this end of one apart, never had to.

The nut might be a split unit which needs adjusting, or these nuts might not be secure in their mount. My clone has a allen headed adjusting retaining screw, been a long time since I messed with it, can't remember particulars.

I'd do some snooping, bet somethings loose.

[C. Tate]

I had a incedent once like this and found out the handle had a keyway that was worn to the point I could not believe it still worked. The problem was not slop in the screw or nutit was slop in the handle. It too would rotate 180 before engaging.

[doug]

I worked on one that hand 6 complete turns.
we still used it. it was a little tricky.

[SGW]

How did that happen? I don't see how that's possible, unless there was gearing involved. Can you give more details?

[docn8as]

sgw.....my ancient union twist drill 6x18 srfc grdr has 1 3/4 b/lash on x/feed...apprantly just screw/nut wear....machts nichts!!! mach runs in tapered brass bushs w/ flat belt .....take ur timew/light cuts , reverse part & this heavy old beast grinds true... head also swivels for tool grndg. table slides on ladder of plain rolling bushes for rungs ....have been unable to get any info on this monster from just talking around....guess the most obvious would be to contact maker ...duhhh! ( fat chance of info on 80+ yr????? mach ),
best wishes
docn8as