Boxford Model C leadscrew half-nuts

An excellent ‘fix’ and a useful video ... Well done, Sir

The price of spare half-nuts should have plummeted !!

MichaelG.

A good fix which the lathe can still be used with the old nuts. Remember that there may be some backlash between the leadscrew and the nuts and allow for it. That inlay I made was using the old nut, but much easier for me as the leadscrew is 1" diameter and makes internal threading easier. I have done 3/4 x 5 Acme by roughing out most of the thread and then finishing with a tap from Tracy Tools.

Yet another way of skinning the proverbial cat!

Splendid! You now have plenty of time to search out a more permanent solution. Probably several years!

Howard

Wishful thinking about the price of spares, but here's hoping!

I had a look for Acme 3/4 x 8 TPI taps and the only one I could find was on eBay from a Chinese supplier. Nevertheless, I like your idea of roughing out first and will bear it in mind if I ever need to attempt this job.

I'm guessing this "temporary fix" may see me out, but I may do a "proper job" (with a threaded insert) at some stage just for completeness. And then again, if I can buy new half nuts for £75 that doesn't sound like an unreasonable deal either.

Certainly an interesting fix.
I notice the rotation of the bolt also applies some longitudinal movement so there is potential (with good nuts) for using this to take up backlash for anyone using the lathe and vertical slide for milling.

Re the screwdriver slot. Perhaps one at the front, ie threaded end, or a hex dilled in would be avantageous.

Not suggesting you buy these, but it shows re-threaded Southbend nuts

SB Half Nuts

AJAX

At 3:11 into your video where it is just possible to catch a glimpse of the operating cam it is quite clear that the peg has worn the top right hand end of that slot. I would imagine the same would be true of the other slot which would have allowed the bottom to not be closed up fully. The top is probably the same.

Whilst your remedy obviously has got over the problem it looks as though my thoughts were correct.

Did you examine them? Or is it all just my imagination?

Wow, they are expensive! New ones can be bought for less.

David, you made me doubt myself there and I had to rewatch the video. To save others the effort I have linked directly to the time you mentioned. I don't see any excessive wear but the next time I remove the apron (which probably won't be long) I will have another more careful look.

Bazyle, that's a really nice idea and one that I might try. I particularly like the idea of a hex socket and know there's a tool to make one on a lathe but the name escapes me at present.

In any case I may remake the studs at some point maybe with a little more care and better choice of materials. I used some 3/4" EN8 as that's what I had to hand. What alternative material would people suggest - EN19? But then again I'm cheap and like to make do with whatever I've got.

A photo in case people don't wish to view the video...

Rotary Broach? Mike Cox has written an article in MEW on making one.

Howard

That's the tool, thanks.

I looked carefully at the advert and was confused. There was mention of the nuts being original, but the threads looked like steel inlays. The seller should have cleaned the muck out of the threads, though, before taking the photo's.

The threads looked like they were inserts brazed in. Not to worry anyway as all fixed for now, and if I decide to replace it may be with new imports from Oz.