> On Jun 29, 2015, at 20:56 , Mark Pfeifer  wrote:
> 
> It looks to me like the jaws have recesses for springs. Maybe the previous
owner soaked it in acid, because there are no springs at all.
> 
> Anyone know a source?

You might get lucky and find a ballpoint pen spring that fits, but I've made
coil springs for 3-jaw chucks by winding guitar string around an appropriately
(under)sized drill bit, held in a vise. It's worth trying!

Adam