new chuck key

Hi all, im making a new lathe chuck key from silver steel, im ok with the hardening but would welcome advice on the temperature that it should be tempered at. Thanks Tony

Hi Tony,

As it's going to be subject to a lot of torque and will be dropped regularly(!) and it doesn't need any cutting attributes, I'd take it right down to blue.

Neil

I've just made one, but I used ordinary mild steel and case hardened the business end, which is now glass hard. Cheaper than silver steel too.

Gary

I made one awhile back for my four jaw chuck so i could move two jaws at a time, never hardened it at all, just mild steel, works grand. Should i have hardened it?

Edited By mark mc on 16/04/2013 16:03:24

I have made numerous for mine out of mild steel and never hardened any. I would prefer to bend the key rather than the chuck.

Jo

I cheated when I made one for a 4" Burnered 4-Jaw

The square on the end of an old HSS Tap was just the right size. ... so I drilled & tapped the end of a mild steel rod for the body, and Loctited the tap in place.

MichaelG.

Michael

Your chuck key worries me!

In my experience, HSS taps are specially designed to break. When they do they leave jagged shards of steel that could injure you.

Ian P

Ian,

No worries here ... The full diameter of the Tap Shank is counterbored into the body, and Loctited.

[and, by the way,  there is no reduced diameter "neck" on this particular tap]

MichaelG.

.

Edited By Michael Gilligan on 16/04/2013 20:58:32

Edited By Michael Gilligan on 16/04/2013 21:12:07

Hi Tony Bastic

A while back I needed a key and all I could find at the time was a longish 12.5mm Hex cap screw. I cut of the head and ground four flats on the end. Then brazed the other end to a piece to mild steel to make a handle. (With key end protected in wet rag to stop the brazing heat affecting the temper). It lasted for at least ten years..... well at least until I sold my old flat belt change gear Colechester.

Good quality cap screw steel is tough. and you don't have to harden it. It also machines rather nicely.

Cheers

John