Shopsmith Forums

Good evening. I inherited three very good lathe chucks from my FIL. Only problem is that they have M33, 3.5 threading.

I have a 1"8tpi adapter for the spindle and got a 1"8tpi to M33 but the threading is a bit short and does not reach very far into the chucks, which worries me.

Does anyone know ...

My 'thinking' was that the table tubes would prevent the assembly 'moving in'.
Had not thought of the lathe rest. A second 'post' in the rear would suffice there.

Yes no tubes allows 'moving in'.

I think gluing the flange back on AND moving it to the front will work.


I have super-glued the ...

Majones1 wrote: Sun Jan 02, 2022 3:44 pm I would look for how it seats in the carriage and if there is excessive wear on the pinion chamfers and the carriage seats they press against.

No unusual wear that is obvious but it IS over 65 years old... And I cannot attest to how it was used for all but the last few months...

Looks to me like the ring/washer had a chamfer to match that of the pinion body and that connection is what failed. Def looks like they are two pieces when looking at the unbroken one.

I went ahead and ordered a full assembly from ebay but here are a couple closeups of the break fir anyone interested in the welding question. I have 0 knowledge of welding and would not know if this is doable.


Broken pinion...
PXL_20220102_175536021.jpg

Reference unbroken pinion...

IMG ...

Thank you. Are the pinions steel or aluminum? Can they be welded?

There is an original full carriage assembly for the Mark V on Ebay but there is also this...
...which says it is also for the Mark V.

Will this fit and work with my original Mark V from 1954?

So this happened while working on a nice little bowl on the lathe...

broke.jpg That ring was attached to what I believe is called a carriage pinion of which there are two, one on each end.

But the shopsmith.com parts seems to indicate that Shopsmith 500 Carriage Pinon 501392 is not available ...

I got the electric sorted out and remounted the head unit on the rails. As the old switch was still working fine, I re-used that.

I found that the speed dial that tells you what speed it is at was not spinning when using the speed control so I took that off and found that the gear in the speed ...

I have a little crud to clear out...but for having sat unused since the '80s, according to the seller, not to bad...