Best metal for a chuck wrench?

Winegrower said:
At some point, it may be better for your chuck key to fail than your chuck.
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I have only had my lathe for about the last 10 of it's past nearly 50 year life and know the business and owner where I got it who had it for another 20 of those years. I do not know who made the key but it has been in and out of the 10" chuck a good number of times. The handle is straight and I have never put any kind of cheater device on it and while I have put some good effort into tightening into it on some larger parts I am neither strong nor abusive and the chuck is still in excellent condition. I got the key with some twist and wear which has become worse. I'm removing and installing my chucks from the D1-6 spindle often several times a day and the broached squares on the machine are perfect as they are very hard. If I were concerned about the chucks failure, I think I'd "engineer" in a weeknes to snap off or use a "T" handle that was less strong than the 1/2" CRS that is on the key now. For the same reason things like wrenches, Allen keys and socket extensions are not made from CRS, it was my choice to use a material that at least, I feel is more suited to the task. I do not think your suggestion of using CRS is bad since I know from experience that it works. I will respectfully and politely disagree with you on it being the "best" choice. I may be wrong and I am open minded to that being the case, I have a history of being wrong and I welcome the reasoning, as both a learning point as well as a simple yet interesting subject. I certainly value your opinion and comments.
 
The new (to me) 6 in. Buck chuck that I recently bought did not come with a chuck wrench. I already had one that came with my old Buck. It is a much better fit in the new chuck. If the chuck wrench does not wear/fail, what is the next weakest component?
 
MrWhoopee said:
The new (to me) 6 in. Buck chuck that I recently bought did not come with a chuck wrench. I already had one that came with my old Buck. It is a much better fit in the new chuck. If the chuck wrench does not wear/fail, what is the next weakest component?

In my case, I can only hope the next weakest thing would be my biceps.:grin: That way the chuck key would have a long and happy life.
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For bigger chucks, I have made the body of aluminum and pinned a steel square drive head on it. The lighter weight seems to be significant...at my age, anyway. :)
 
It's really cool to do like @pontiac428 did and mike a tool nice that will be in the shop for years and in hand often.

in my decidedly unscientific analysis the pinions in my 3 jaw and the sockets on the D-1 cams are around 55C. 1144 is supposed to be 25 RC. I am not a fan of gummy CRS which has rather poor characteristics for a tool IMO. The key for my 4 jaw is hex and softer than the 1144 but harder than the CRS. The screws of the 4 jaw chuck are also more like 30RC? Those screws on the 12" 4 jaw might be broken by an over exuberant individual. I'm pretty sure the 3 jaw (South Bend branded from the 1970s) would have been broken by those who came before me. If I break my chuck, I'm not going to blame my tool, following that logic I would have made it from Aluminum. I keep "Stress-Proof" and 4140 in stock because it fits in my collets, machines very nice and produces strong working parts. Lack of good weldability is the biggest negative. Yea, it cost some more but I don't use enough to see that as much of an impediment.
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