Soft jaws for a 3 jaw chuck

[stevec]

Last winter I decided to start a project to convert a surplus Cushman 3 jaw chuck to a "soft jaw" chuck for my 12 x 36 lathe.

The chuck didn't have the necessary 2 piece jaws so I wondered if they might be available.
Cushman didn't reply to my query for jaw possibilities so I thought about machining the existing ones.

The jaws laughed at my file hardness test. The file lay trembling in the file drawer.

So, with the recommendation of a buddy (on another forum) I put the jaws in the coals of my then constantly burning airtight stove.
Removed them to the constantly at hand ash can.
20+/- hrs. later the next day, after cooling slowly the file had it's revenge.

The jaws were soft enough to cut with my homemade bandsaw.

   

Next was the drill test to see if they could be drilled and tapped.

   

And now on to step 3 to machine the new, low tops on the jaws.

       

Here's the project now stalled, awaiting a threaded backplate for the lathe and finally soft jaws.

   

There has been some talk about re-hardening the jaw bases but I think I'll leave them as they are because I suspect they will get relatively infrequent use.

Back plate progress will be reported when and if it happens.