3 jaw questions

[Tozguy]

if i'm not mistaken, i remember seeing somewhere that 58mm x 8 tpi was the spindle dimensions
i have a shenwai 1236, i should pop the chuck off and see if i can verify.

Doc, I have seen Imperial threads on a metric machine and metric threads on a Imperial machine, but I have never seen a thread spec with a metric diameter and an Imperial pitch, at least not by design. Woe is me.

 

[menace]

Imho I would chuck the backing plate in a known fitting chuck on the lathe , true it to zero, then set up an internal thread boring bar, true it to face of backing plate, then set cutting tip inside thread snug, then loosen till you can turn chuck by hand with half nuts engaged and quick change set for proper thread. Let thread bit tip move in as if cutting, if it stops , its probly metric, if it goes all the way thread is probably correct but not deep enough, you can check thread on spindle also, just set cutting tip for external threading TURNING by hand with NO power! Hope I haven't confused the issue and explained it enough . My 2cents , good luck!

 

[Ulma Doctor]

Ulma Doctor, that would be great if you can do that.
Brian

my chuck is stuck on, it may take awhile to free it up.
i'll post my results when i get it off