Brass ACME nut repair

Is it something you can take off, measure up and have someone make for you for less? If they did this, would you be guaranteed to have less slop?

I can take off the part and mail it to whoever to replicate. I would obviously pay for it, but not anywhere close to $750, of course. I looked at the nut, it looks badly worn, I do not think that it was this way originally -- but, surely I would have to ascertain that again. I may be able to do something with my mill, original nut, and the McMaster nut. (as in, mill out the original nut, insert the mcMaster nut and braze in)

"Ignoramus22312" wrote in message news:nsCdnaCGB6j47-bVnZ2dnUVZ snipped-for-privacy@giganews.com...

You can also buy the appropriate acme tap and make a new nut.

The nut part number you list above is for a right-hand nut. You might want to take a closer look at your old nut/screw---most I've seen are left-hand.

Bill

i deal with it by ignoring it. There's no climb-milling issue on a lathe. Look into Moglice

$150

Good point, I think that you are right.

4) Split the nut and make it adjustable. I've done this on two machines, a lathe and a surface grinder.

On the lathe, the nut was rectangular and there was enough material around the thread to install two guide pins and two adjusting screws. Drill and ream for the guides before cutting the nut in two.

The grinder's nut was cylindrical with a thin wall. I cut it in half and turned a fine male thread on each piece. A coupler with matching threads and the same OD as the nut allows for lash adjustment.

None of these options will account for the inevitable unequal wear in the lead screw.

First off, make sure everything is tight. 1/8 in is a boatload of slop for a

5 tpi nut. It mean your threads are only .075 thick at the base. It is a good chance that some of the slop is coming from the nut being loosely mounted or the handle on the screw not being mounted tight enough.

If the lash drops down to something reasonable, learn to work around it and buy a new nut when one falls in your lap.

If it is still that large, take a good look at the screw as well.

McMaster carr sells a left hand bronze cylinder nut in 3/4-5 #95090A412 for

38 bucks. You could probably machine something up to fit.

Paul K. Dickman

Ultimately, what could happen is that the McMaster is too loose or too tight and then you are almost back at square 1... But it's worth a try compared to $750!

Yes. They are very thin. The whole brass nut looks like totally worn shit. (but the steel screw looks good, superficially).

I wish.

I rather like item 95270A523, I think that it will be easier to adapt. (and cheaper too)

i

I think that I will buy one today.

i

Here is how I did similar repair on 13: S.B. lathes.

Errol Groff

You can always return it if it doesn't fit the lead screw properly BEFORE modifying it.

If you are going to braze it in, think about getting a piece of spare male thread to put in it to make sure it holds size during the process. Don't know if that will help or not in an overheat situation, but it's low cost insurance.

Regards, Joe Agro, Jr. (800) 871-5022

01.908.542.0244 Automatic / Pneumatic Drills: Spindle Drills: V8013-R

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What about facing?

Very nice page Errol. I will see first if I can keep the screw, but if not, I will buy a screw also.

It is in such a bad shape, that doing so would not help.

The lead screw is just $22 at McMaster-Carr, I will just buy it if I find a lot of wear on the existing one, but I expect (and saw) most of the wear on the brass nut. So I will start with the nut first.

Similar to an earlier suggestion, but slightly different: split the nut, so it is like a pair of jam nuts, and then turn one half so the slop is taken out. Then, cross drill and pin, or silver solder, or come up with some other method of holding them.

thr split nut ideas are great if you have little wear and want to lessen the slack, however, if you have more wear in one part of the screw than the other, this is likely to bind when you get out of this sweet spot...

just a thought.

Fixed an HF XY table with similar woes by compressing the nut in a BFP in small increments until the lead screw had no lash. Worked well. JR Dweller in the cellar

Ignoramus22312 wrote:

The free play on my lathe is 0.052" on the cross slide, 0.038" on the compound. The compound at 29 degrees would be more likely to slip forward and dig in if the tool had a large top rake, but I know better than to grind it that way. A top rake of 10 - 20 degree doesn't cause problems. I tried 60 degrees once after seeing it in an old book and did have trouble.