13" Double Tumbler QC Gearbox Question.

[dwall174]

I recently picked up a 13" South Bend turret lathe & I have most of it disassembled & I'm starting to clean everything up.
After cleaning the parts I double checked them for damage & worn-out areas. One item that seems different than others I've seen is the tumbler shaft.
Mine has 4 slots for the tumbler gears instead of the normal two slots.


I could understand it if the original slots were damaged & someone just machined new slots, but both sets of slots look fine.
One set of slots is .125" deep & the other is only about .100" deep. Both gears fit fine on the deeper slots, but only one gear fits good on the shallower slot!

Has anyone seen this done, and what would be the reasoning behind it?

Doug

 

[SLK001]

Maybe someone added an additional felt track for oiling.

 

[markba633csi]

Maybe a shop-made shaft? Might not be original- and possibly made without the benefit of an indexing device
-M

 

[dwall174]

Maybe someone added an additional felt track for oiling.

That's possible, but then why make the slots the full length of the shaft? The felt wicks are only used for about 1" at the end of the shaft.

Doug

 

[dwall174]

I never found out or figured out why the previous owner added the extra set of grooves!

I did however notice another problem with the QC gearbox, both of the tumbler levers have elongated holes where the tumbler shaft runs through the castings.



Does anyone know if there may be a print for these castings?
Or has someone figured out the center-to-center dimension from a really good condition lever?

Knowing the correct center-to-center dimension, the casting could be bored out & a bushing installed!

Doug