Need to make a new chuck key.. what material?

[woodchucker]

I made a chuck key a few years ago, and tried to heat treat the business end. But I guess I failed, as the tip twisted under load. I chopped off the tip and remade it.
it's a 1/4" square. I want a longer one , about 12". This gets in the way of the my carriage which has an indicator attached, or the tension rod for the belt (if I take the tension off so I can swing the chuck).
The last one was made from 4130 I thought, or 4140. It was given to me by a friend. Either it wasn't , or my heat treating sucked.

What would you make a long chuck key out of so it didn't twist? Only the last 1 inch will be narrowed the rest will be probably 1/2 inch tapering to 3/8 gently then 3/8 " will be 1/4".

 

[mmcmdl]

Use a 1/4" socket extension Jeff , unless you feel the need for turning something up .

 

[Martin W]

1018 or, 4140
Martin

 

[Jubil]

Probably not what you are looking for, but have you thought about using socket extensions and/or adapters?
Looks like mmcmdl was typing at the same time I was.
I would try a 1/2” extension with 1/2” x 1/4” adapter.

Chuck

 

[Stonebriar]

W1 drill rod

 

[woodchucker]

I have been using a socket extension to extend my reach.... I busted one end off, and re-ground a new end, it's been fine for a couple of years since.
It's a sloppy fit though when trying to get the last little bit adjusted. backing off one end, then pushing forward on the other.. would like a more solid feel.

can't get a 1/2 in with the adapter. The adapter is too much added space.

 

[woodchucker]

1018 or, 4140
Martin

1018 would it be strong enough?

4140 or 4130 already showed a limit.. but again could have been my heat treat since the shorter version hasn't twisted.

 

[woodchucker]

I would order new O1, as this is way to big, I could order 1/2 O1 or W1

 

[mmcmdl]

440 C Stainless . Heat it up and air cool it . Either that , quit doing this and give that chuck a break .

 

[woodchucker]

440 C Stainless . Heat it up and air cool it . Either that , quit doing this and give that chuck a break .

I give it a break, it keeps breaking back.
Don't think I have ever worked with 440c... I have a ton of stainless, not even sure which until I work with it.
Some 304, 316 and some other stuff. Got it from a machinist who worked on nuclear reactors. He retired and gave me a Sxxx load of stuff.