# Enlarging spindle hole



## arnie (Jan 17, 2022)

Anyone use a reamer to enlarge the spindle borehole? I have a 9 inch South Bend that is 3/4 inch. I wonder how much bigger I could go if it's even possible?


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## SmithDoor (Jan 18, 2022)

Very little 
The feed gear limits the size it part of the spindle. You can not even go upto 13/16". The spindle is same as the 10K.

Dave 



arnie said:


> Anyone use a reamer to enlarge the spindle borehole? I have a 9 inch South Bend that is 3/4 inch. I wonder how much bigger I could go if it's even possible?


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## arnie (Jan 18, 2022)

Thanks for that information. It was suggested by someone that had done this but was not a South Bend lathe. I will have to ask him what lathe he has.


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## awake (Jan 19, 2022)

Check to see whether the spindle is hardened first!


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## SmithDoor (Jan 19, 2022)

You can cut the the spindle 
The problem is threading gear .
You need to make a new headstock to fit a larger gear.  

Dave 



awake said:


> Check to see whether the spindle is hardened first!


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## MRA (Jan 21, 2022)

I use a Boxford lathe at home, which is a SB9" clone.  I came by an 8" 3 jaw chuck, which is way bigger than the machine can really handle - and of course one must be careful how far out the jaws are, or they'll clout the bed!  But - the chuck is deep, and has a large hole up the middle, which helps a lot with holding things which otherwise (in the 4" chuck I used previously) would be a pain.  It's not as useful as a 2" spindle bore, as on one machine at work.

I suppose there is a lot of overhang on the front spindle bearing, and the setup will not be too rigid - I tend to use the tailstock for parting, for example.  But on balance, given my tight space constraints which forbid a larger lathe at home, I'm pleased with the big chuck.

(Edit - I knew I had a photo on here somewhere - here is the link, though the idea is not very complicated! 
Small lathe, big chuck )


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