Subject: Re: Identification?

From: [email-masked] (MR WILLIAM A HOCHELLA)
Date: Fri, 15 Mar 1996 09:11:05 EST

To All,
As mentioned in previous e-mails, a dead giveaway for a cast part is 
the mold line. This is usually left on less expensive or less visible 
objects. 
If you are using found metal, you have to remember that the reason 
you found it is because somebody threw it away or lost it. I have 
heard about knifemakers using used truck springs as a source for 5160 
steel. Most used truck springs are broken truck springs. Be careful 
with what you find. There are spark test references that can help you 
determine families of steels. Keep samples of known composition and 
known thermal histories and compare them to found or unknown pieces. 
As a back up cut off a little piece and air cool it. If it hardens 
you have air hardening steel tool or other wise. Try again with oil, 
etc. I have found that the investment in known materials is small 
compared to the pain, real or imagined, that found stuff can cause.

Regards,

Bill Hochella