Anne,
In drawknives and most tools manufactured with carbon steel and iron ( even into the mid-20th century) a steel bit would be either laid on the iron or sandwiched (as in an axe) and forge welded together. After final shaping with the hammer the tool would be annealed (slow controlled cooling) then polished and ground, reheated to the phase transition temperature (approx. 1500 degrees F) and then rapidly cooled (quenching). The faster the rate of cooling the harder the steel is left. Then the surface is scrubbed or ground and then reheated on top
of another heat source (today in ovens). A period smith would look at the band of colors that form on the polished metal and when the edge got to the correct color (deep straw or light purple for wood cutting tools) then the tool would be dunked in water to remove the residual heat.
On such old tools look for a weld seam on the back or side. Also the steel will oxidize a bit differently from the wrought iron and usually the steel but or edge will look darker when seen under a bright direct light.
Everyone now ready to go out and make drawknives?
(in a previous lifetime I was a museum blacksmith and gunsmith at Colonial Williamburg
).
Cheers!
Dave
David Harvey
Conservator, Los Angeles CA
------Original Message------
From: Anne Lane
Sender: Museum discussion list
To: [log in to unmask]
ReplyTo: Museum discussion list
Sent: Nov 8, 2007 1:20 PM
Subject: [MUSEUM-L] Metal ID Question
This may actually be a really dumb question, but I’ll ask it anyway. How do you tell iron from steel? I have a drawknife, date unknown, obviously handforged, stamped with an illegible maker’s mark, blade made of ferrous metal. I don’t know how to tell whether it is iron or steel. Often you can tell just from the context, but I don’t always have that. Must I spend the rest of my career typing out the words “ferrous metal” when a four- or five-letter word would suffice?
Thanks,
Anne T. Lane
Anne T. Lane
Collections Manager
704.568.1774 x110 phone
704.566.1817 fax
[log in to unmask] <mailto:[log in to unmask]>
The Charlotte Museum of History and Hezekiah Alexander Homesite
Where History Has a Home
3500 Shamrock Drive
Charlotte, NC 28215-3214
www.charlottemuseum.org
Featured Exhibits:
ToyTime: Larger-than-Life Folk Toys, September 8, 2007 to March 9, 2008
Flags Across The Nation: Quilts of Patriotism, September 11 to November 11, 2007
Charlotte Neighborhoods: Brooklyn to Biddleville, Now through January 25, 2008
Sent via BlackBerry from T-Mobile
|
