Thicko chuck key question

[Gragson]

Lost the 1/4 and 5/16 keeps slipping.

So I've just ordered a Jacobs K2 for a 1/4" chuck and a K3 for 5/16" chuck, measuring the key locating hole so hope I've got that right?

I've seen keys listed for 10 / 13 / 16mm - if that's just the chuck size, are the keys standard depending on chuck size? I wouldn't have thought so and maybe why my key slips cos it's wrong?

 

[Agroshield]

Keys are specified by hole diameter and No. of teeth (not much help if you do not have one to count). Look at:

http://www.jacobschuck.com/MagentoShare/media/documents/jacobs-catalog.pdf (page 18)

and

https://www.newmantools.com/jacobs/keys.htm

 

[skotl]

Apologies for hijacking the thread, but do chuck keys need to be hardened? I need one for a 4 jaw and am too tight to buy one when they don't seem that hard to make...

 

[MattF]

No.

 

[Gragson]

Apologies for hijacking the thread, but do chuck keys need to be hardened? I need one for a 4 jaw and am too tight to buy one when they don't seem that hard to make...

Would think you would want a key to lose the battle against the the chuck rather than the other way round

 

[skotl]

Would think you would want a key to lose the battle against the the chuck rather than the other way round

Good point! Right - that's tomorrow's milling project sorted out