|Helves, heat treat, horror
||[Jun. 5th, 2004|10:59 pm]
Having some free time last night, I headed to the workshop and decided to finish off at least one project. |
I started off by pre-heating the forge for the heat treating of the axe head. This is the polished head you can now see in the photos mentioned earlier. While the forge was heating, I went to work on the axe handles.
The handles are cherry, from a tree half-destroyed by last years storms. They have been vacuum stabilized with diluted polyacrylic, and had a few weeks to cure now. I used various grits of sandpaper to smooth them down and clean them up, finishing with a 220 grit.
For a finish, I used a boiled linseed oil with japan dryer, which should give a nice finish and still let the wood oxidze -- the cherry should turn darker over time. I'll put an additional two coats before I declare them done.
After finishing the first handle, the forge was at a good orange heat. THe base of the forge is a cast, dense refractory, which holds heat fairly well. Since I wanted to minimize oxidation, I next turned off the propane, and then placed the axe head in the forge. The retained heat from the floor of the forge was enough to heat the blade up to critical, which I verified with a magnet. I had also turned the lights off so I could judge the color of the blade, but to be honest, with the high polish on the axe head (I took it down to a X30 Norax belt finish, about 500 grit)I couldn't tell the difference between glowing metal and the glow being reflected. Fortunately, the curie point is just around the critical temperature for heat treating, so I gave it until the magnet-on-a-stick stopped sticking to the metal, and another few minutes to ensure it all passed the critical temperature, then quenched.
Since the steel used for the axe head was 1050, I just quenched in water. The axe head came out OK, but had a bit of warping. This is most likely due to different shrinkage rates during quench. It didn't happen on the other axehead, though. Not sure why, it may be because the other axe head wasn't polished, and so had a nice thick layer of scale and decarburization on it.
I tempered at 400 F, and will try to take out the warp with a wooden mallet and leather-covered anvil tomorrow. If it proves reluctant, I'll heat up again and re-straighten, and try a less viscious quench, maybe a fast oil.
I finished off the 2nd handle, and mounted the "primitive" axehead on it. You can see the pictures at the above url.
Goal for next week: Finish off the 2nd axe head and send it off to the school I did the demo at. finish one chef's knife. FInish 2 of the feast knives. This shouldn't be too hard.
(oh, the horror? I watch _Necronomicon: The Book of the Dead_ this morning while making breakfast. Bad, bad movie. Ok, so I actually kinda liked it. I'm a Lovecraft fan, can't help it.)