Saturday, March 27, 2010
306. Hardening and Tempering a Cold Chisel.-After a cold chisel is forged and annealed, it may be hardened and tempered as follows:
1. Heat the end to a dark red, back 2 or 3 in. from the cutting edge.
2. Cool about half of this heated part by dipping in clean water and moving it about quickly up and down and sideways, until the end is cold enough to hold in the hands.
3. Quickly polish one side of the cutting end by rubbing with emery cloth, a piece of an old grinding wheel, a piece of brick, or an old file.
4. Carefully watch the colors pass toward the cutting end. The first color to pass down will be yellow, followed in turn by straw, brown, purple, dark blue, and light blue.
5. When the dark blue reaches the cutting edge, dip the end quickly into water and move it about rapidly. If much heat is left in the shank above the cutting edge, cool this part slowlyso as not to harden the shank and make it brittle. This is done by simply dipping only the cutting end and keeping it cool -while the heat in the shank above slowly dissipates into the air.
6. When all redness has left the shank drop the tool into the bucket or tub until it is entirely cool.
PHOTOGRAPHER'S JOURNAL: After following the beam of sunlight across the shop it was inevitable and just that the last sunshine fell where the smith sent sparks flying. Beside the anvil is the crank he turned to make the coals glow white hot until he deemed the iron ready to be worked. That knowledge, I'm told, was passed down through generations in a ceaseless regimen of repairs and improvements and occasional bits of virtuoso display all of which pressed on like the seasons. Since blacksmithing can easily be a two-person task, one can only imagine much was said in words and deeds around this anvil.
Normally I go to old places to look for traces of the past. Here the scene was nearly intact, the past was all around me, and what was striking was how it had remained so long. The men who worked here did not do so haphazardly. They were resourceful and hard-working. And then they put down their work and stopped, and the place is very quiet now and drafty, too cold for the mice.