# Sb 16/24 X 60 Gap Lathe With A Stripped Split Nut



## seilert (Apr 9, 2016)

Whats the best way to fix a stripped split but on my 1920 sb lathe?

Sorry if this is an age old obvious question!  

Thanks!
Sean


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## LucknowKen (Apr 9, 2016)

You could try to layer the half nut threads by brazing then re-thread, Or even JB weld if you are adverse to brazing. Otherwise remove the threading, pin in a threaded bushing and then split the bushing with on a band saw. I am no expert and
I have not tried either method, but i have an old Reed lathe with the same problem.
Lken


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## seilert (Apr 9, 2016)

I got it out ... The hard way, probably 


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## seilert (Apr 9, 2016)

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## seilert (Apr 9, 2016)

From what I can tell I need to remake that threaded split  bushing and silver solder it in. Am I on the right track?
Those threads really are bad, right? I'd feel pretty silly if there is an adjustment !! (But they don't seem to fit into the lead screw threads all that well. )


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## seilert (Apr 9, 2016)

LKen it looks like yours are soldered in too. 


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## LucknowKen (Apr 9, 2016)

The attached picture is courtesy of Brett Flemming. I have not tackled this issue yet. I think the half nuts in Brett's picture show the brass bushing pinned, then threaded, then spit. The parts in your post look pretty tough. IMHO they can be re brazed and re threaded though. From what i have read you could even try lead solder, but it does not last under heavy use.


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## seilert (Apr 9, 2016)

No px?


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## Silverbullet (Apr 9, 2016)

Many eons ago I remember our big lathe half nuts wore out, but back then we just clamped to the shaft after carbon blackening and poured babbitt in . The carbon kept it from sticking to the edges and the threaded shaft. after cooling and drilled for lube it would last a few years at least. Old lathes had Babbitt bearings every where.. If it were mine I'd get a piece of bearing bronze turn it to OD with flanges ,then I'd saw it in half ,clamp the half nuts mount the whole assembly in a four jaw and bore and thread. Now it's impossible to do on the lathe with out a tap so you need a friend to loan you his lathe to cut the threads. oh well not much help here.


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## Andre (Apr 9, 2016)

LucknowKen said:


> You could try to layer the half nut threads by brazing then re-thread, Or even JB weld if you are adverse to brazing.



JB weld is slightly abrasive and would potentially wear your leadscrew. With all due respect, I believe a way-repair epoxy such as Moglice would be a better option. You could even cast it around the virgin tailstock end of the leadscrew to form your threads.


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## seilert (Apr 10, 2016)

Thanks guys!  I like the simplicity of the epoxy route and the Babbitt idea sounds fun (at least it would be a new experience) but I think I'm going to go for the gold .. or bronze as it were.  As luck would have it, it was messing around with my buddy's Craftsman Atlas lathe that was sitting in my workshop collecting dust that got me interested in getting this thing in the first place. I guess I'll have to use it to turn and thread a bushing before I let it go.  Who knows .. maybe after I fix my split nut I'll put his lathe in my 4-jaw and thread it (the Craftsman lathe, that is, and yes it almost fits) .

MSC sells what they call "Made in USA - 1 Inch Inside x 1-1/2 Inch Outside Diameter, *Cast Bronze Sleeve Bearing*  3 Inch Overall Length".  I'm assuming I'll be able to turn and thread this and then silver-solder it in, right? 

Since I'm going to have to take a torch to it with the bushing route anyway, I'm thinking I might try to braze on new material and just rethread what I've got as LKen suggested?  I have the tools, but I'm not sure I'm good enough -- any pointers if I try to give this a shot?


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## LucknowKen (Apr 10, 2016)

Brazing and rethreading would be the first step IMHO. If that fails then re-bushing. Then babbitt.
I do not know which lathe you are working on, but i believe the bushing you mention (1 Inch Inside x 1-1/2 Inch Outside Diameter) would be to large for the SBL 9s i have to measure from. .


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## seilert (Apr 10, 2016)

This is a SBL 16/24x60 gap lathe with a 1 1/8 acme 8 TPI lead screw. 1" is probably cutting it close but smaller doesn't leave me a flange. As all bronze is not created equal I'm wondering if that's the ideal base material for this or if I should pick something else. 


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## LucknowKen (Apr 10, 2016)

seilert said:


> This is a SBL 16/24x60 gap lathe with a 1 1/8 acme 8 TPI lead screw. 1" is probably cutting it close but smaller doesn't leave me a flange. As all bronze is not created equal I'm wondering if that's the ideal base material for this or if I should pick something else.
> Sent from my iPhone using Tapatalk


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## seilert (Apr 10, 2016)

Nice!


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