Craftsman 109.21270 3 jaw ?

[jpackard56]

I have a question about a 3" 3-jaw that has been packed away very deeply for about 40 years with other items from my Craftsman 109.21270 I'm laid up from work and finally have some time to dig through boxes and cans in my shop. Came across this 3-jaw and I've never seen one quite like this and was hoping for some insight on its history and/or proper use? I've given it a quick clean up and it seems to function fine. I'm just not sure how it should be used because the contact points of the jaws would be very limited compared to any other 3 jaws that I've worked with. Is it possible it was made to hold some sort of collets? Any thoughts? Whenever I've used this lathe I used the original 3" 4-jaw or a 1/2 Jacobs so never saw this before down in the stuff.

 

[markba633csi]

Never seen one, maybe for holding the end of an armature, for truing commutators? Hard to say

 

[jpackard56]

Yep, I've never seen another one, but surely somebody out there has. I agree it could be for armatures. I've not done those, but a fella I know that used to do a lot of that kind of work for auto restoration just used a Jacobs and/or regular 3-jaw depending on the size of the armature.
Thanks for looking !