4-24-11 It's Easter Sunday and I am heat treating my first plane blade. This one is 2 x 6 x 3/16 A2 steel. I spent some time online researching the proper method for treating A2. Most sites had information similar to the method below. Preheat: 1100/1250F (595/675C), equalize, 1350/1450F (775/790C), equalize. High Heat: 1750/1800F (995/895C), 30/45 minutes at temperature. Quench: Air, positive pressure vacuum to 150F (65C). Temper: 400/1000F (205/540C), hold 2 hours at temperature, air cool. Temper twice. I will add a 700F preheat and equalize at the beginning of the process, quench in still air in my shop, and use 375F for my temper in the kitchen oven. To allow full equalization at the this lower temp, I will allow 2 hours per temper. I am aiming for a Rockwell C 60 to 61. The blade after shaping and sanding to 100 grit. To prevent oxidation when the steel reaches critical temperature, the blade needs to be wrapped in stainless foil crimped around the edges to be air tight. I cut some pieces of firebrick to hold the blade on edge in the furnace. I didn't get any photos while removing the blade from the furnace or cutting the package open. Here are the remnants of the stainless packet after removal. When I removed the packet form the furnace, the foil was puffed out slightly but still tightly sealed and I could see the blade glowing inside. I held it with tongs edge toward a small fan until it stopped glowing then cut open the foil. After two runs through the kitchen oven for tempering, the blade was ready for the final grind and honing. I set it up in my Krenov plane and it worked like a charm. I have since completed the wooden jack plane that this blade was intended for. It works beautifully and the blade holds an edge very well. |
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