# Sb Spindle Threads Too Tight?



## VSAncona (Sep 8, 2015)

I recently replaced my Atlas 10" lathe with a South Bend 9A. When I sold my Atlas, I kept a couple of the chucks that came with it to use on my SB. They are Westcott brand chucks and are threaded for a 1-1/2 x 8tpi spindle. They fit on my Atlas lathe just fine, so I assumed they would fit the South Bend as well since the nominal thread size is identical. But they thread on for about one turn and then won't go on any further. Did South Bend use a non-standard thread size on their lathes?


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## DoogieB (Sep 8, 2015)

No, it's a standard 1 1/2 x 8 TPI.

It's possible that the threads on your chuck backplates aren't cut very deep.  I've read that some of the other manufacturer's spindle threads were a few thousands smaller or not as quite as tight a fit as a SB.

On the other hand, I bought two different back plates last year and both of them threaded right onto the spindle.


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## David VanNorman (Sep 8, 2015)

Run a 1 1/2 8 tap thru  the backing plates an the should correct the problem.


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## Andre (Sep 8, 2015)

David VanNorman said:


> Run a 1 1/2 8 tap thru  the backing plates an the should correct the problem.



 $220 tap (Chinese no-name brand) http://www.mscdirect.com/product/details/04874053

Buy a blank and make a new backing plate yourself if you already have a second chuck or faceplate for your SB. 

http://www.collegeengineering.co.uk/BackPlates.htm


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## T Bredehoft (Sep 8, 2015)

http://www.ebay.com/itm/Lot-1pcs-HS...ols-Cheaper-/331646323331?hash=item4d37a94a83

Yeah, it's $55, but that's 1/4 of the Chinese version form MSC.


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## GarageGuy (Sep 9, 2015)

I made a spindle thread protector for a guy with a SB 10" lathe that had 1 1/2-8 spindle.  He said it didn't fit.  I checked, and his spindle (at the register) measured 1.509".  I couldn't believe it, and measured it three more times thinking I had somehow managed to screw up the measurement, but it was correct.  Never seen anything like it before, or since.

GG


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## VSAncona (Sep 9, 2015)

These chucks don't have back plates. The body is threaded. They all fit just fine on my Atlas lathe with no issues.

I did try running a tap (an American-made tap, not Chinese) through one of them and it didn't help. I will measure the spindle tonight and see if it's oversize. I wonder if South Bend made their threads a little bigger on purpose so that you would have to buy their chucks?

I'm starting to wish I had just kept my Atlas lathe.


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## aametalmaster (Sep 9, 2015)

I have a 9" headstock and a 10K lathe. If I make a thread to fit one it won't fit the other one. The 10K is a few thou bigger than the 9"...Bob


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## Andre (Sep 9, 2015)

VSAncona said:


> I'm starting to wish I had just kept my Atlas lathe.



No you don't! Atlas machines are great, but South Bends (put aside brand loyalists and fanboys for a bit) are very solid machines, especially the larger ones. everybody has buyers remorse at some point on a new machine, maybe is's the swearing after you find out it's all broke inside or while cleaning out the 50 years or chips. Once you have everything sorted out, it'll be a good machine.

If you have a second chuck or faceplate, you can set the Atlas chuck on the machine, and with a boring bar and 60* toolbit chase the threads a hair larger. 

It'll be a good lesson in picking up a thread, bit grinding, and making a boring bar.


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## VSAncona (Sep 10, 2015)

Andre said:


> No you don't! Atlas machines are great, but South Bends (put aside brand loyalists and fanboys for a bit) are very solid machines, especially the larger ones. everybody has buyers remorse at some point on a new machine, maybe is's the swearing after you find out it's all broke inside or while cleaning out the 50 years or chips. Once you have everything sorted out, it'll be a good machine.



Yes Andre, I'm sure my buyer's remorse has more to do with the fact that I spent a considerable amount of time getting my Atlas lathe dialed in so that it was working quite well and now I'm having to start all over again with another lathe. I had no real complaints with the Atlas and I kind of bought the South Bend on an impulse -- not sure why. But it's a done deal now so I need to just stop winging and get the South Bend running. It shouldn't be too difficult because it's really in remarkably good condition. It's more a matter of learning all its idiosyncrasies -- like the spindle thread thing.


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