Posted by Brett Wilsey on Sunday, February 29, 2004 at 2:16PM :
In Reply to: Never heard of....... posted by KenW on Sunday, February 29, 2004 at 0:28AM :
It is a variation of 4140. Tube and fabric airplanes are made of 4130 which contains just a little less carbon. Some people call it moly steel. The "L" means it has a little bit of lead to make it machine easier. I heated it with a torch to cherry red and quenched it in oil to harden it. Then heated it again to around 500 F. to temper it. Most suppliers that sell angle iron and square tubing will just look at you funny if you ask them about it. A good job shop/machine shop will usually have some.
Brett