Check myself before I wreck myself (Chuck thread size)

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13 Jul 2015
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Can someone confirm I am reading this correctly and that my thread size is (T23 - 1.1/4" x 8tpi)?



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Looks like it is a little over 1-1/4" diameter. Remember that machined screw threads are rarely the full specification diameter, the crowns being rounded or slightly under max diam. for clearance.

That would make it more likely be 33mm X 3.5mm .

Is it a relatively new lathe or one that is likely to have had areplacement spindle made.
Looked like a 33x3.5 to me as well. I see you have a chuck beside it, assuming chuck fits is there not a stamp on it somewhere with the thread or insert size?
Glad I asked.

So :

M33 = 33mm
1.1/4" = 31.75mm

3.5mm thread pitch is around 7.2 TPI

And yet most chucks come in both options. Thats bound to cause confusion!

It was bought new about 10 years ago. Super Nova 2 chuck. Will see if its stamped on the chuck tomorrow.

Sent from my SM-J510FN using Tapatalk
It's a Fox F46 718 Superlathe

I checked the chuck and the faceplate and neither have a stamping for what thread is being used. There is also no markings on the lathe spindle or around it either.

Looking at the specs here, they mention M33x3.5mm so I am just going with that. I also measured it with a digital caliper and it seems close enough.


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Yep - I linked to the specs in my previous post.

For some reason, I had in my mind that each model could have a range of spindle thread sizes (you choose when you order), so it didn't occur to me to look up the spec.