What is the proper name for the brass guards used on 3 or 4 jaw chuck jaws to protect work piece ?

[jim18655]

I've cut pieces from aluminum cans.

 

[kvt]

Problem with pennies is that they are mostly zink and other stuff besides copper any more. Thus they can also scratch stuff now find some old pennies and they work, put them on the railroad tracks for train to run over and then they work really well.

 

[Tozguy]

Lots of old (pre 1982) copper pennies are still in circulation. You don't have to put them on a railway track, they squish quite well in a four jaw chuck.

http://www.coinflation.com

 

[Cobra]

I like the soft copper from pipe scraps that are annealed and split lengthwise.
When they get mashed up and hard again, just torch them and then flatten in the press.