This was my first attempt at color case hardening. I’m building a Gemmer period Hawken rifle (ca. 1865). I’ll post pictures when it’s finished. I posted some case hardening questions a few weeks ago and thought I’d show some results.
The first photo is the heat treating oven purchased from Brownells. The bone and wood charcoal was also purchased from Brownells. I bolted it to a short cart to make it moveable for storage. I can still park my car in the garage.
By the way… when you buy this much stuff from Brownells they send you a personal thank you letter.
The crucibles (also from Brownells). I purchased 2 of the large size. I cut 3” from the top of one of them to give me a smaller size. I modified the lids so they would slide off easily. The procedure is to pull the crucible from the oven, rest it on the top of the quench tank, rotate it by rolling it end-for-end on top of the tank, setting the lid between guide bars on the tank top, pull the pin holding the crucible lid on, and slide the crucible forward dumping the contents. It takes longer to say it that to do it. I would post a photo of it, but didn’t have anyone around to take a picture. Apparently they painted the crucibles. The paint burned off in the oven. It didn’t seem to affect anything.
I fabricated my quench tank from two 20 gal garbage cans. The outer can has a garden hose faucet attached. This is how I fill and empty the tank. It works great, but I had to caulk the seams with silicone caulk to stop leaks. It still leaks from the handles, but not fast enough that it won’t hold water.
For the inner tank I cut a section out of the middle where the handles were located and fastened the 2 parts back together with machine screws. This allows them to nest closer together so the water is about 2” from the top.
I put a support roller stand in front of the tank to help support the crucible tongs.
The green thing in the bottom is my catch basket. It’s actually a gold classifier. It worked better than making something. The mesh is heavy, just the right mesh size, and it fits the bottom perfectly. I simply cut a hole into the bottom of the inner tank.
The top is fabricated from hardware store steel plate (I think its 16 ga.) and ¼” thick bars. The 2 bars on the top are spaced to allow the crucible lid to set between them. There’s another one under the edge of the opening. This adds rigidity so the top doesn’t sag from the heat. The 2 bolts at the front edge are set through steel spacers. The front of the crucible lid fits under these and they hold the lid in place.
The blue hose goes to a small compressor I used to use with an airbrush. I used it to aerate the water 15 minutes before quenching.
Some of the parts after coming out of the kitchen oven for tempering.
The butt plate was braced with a piece of black iron pipe riveted to a piece of square channel. The toe plate and muzzle cap were screwed to a piece of square channel. I don’t have a picture of it, but I braced the tang and trigger plate by fastening them together with 2 bolts and 1” steel spacers. It seemed very rigid and I didn’t notice much distortion. I threaded a nut onto the threads of the breech plug and put a screw into the nipple hole to protect the threads. The trigger guard also had a nut on the threaded stud.
Parts were packed in the crucible with a mixture of 2 parts wood to 1 part bone. The crucible was placed in the oven cold. The oven was set to a temperature of 1350° with a hold time of 2 hours. The water in the quench tank was aerated for 15 minutes and then the compressor turned off and the hose removed before quenching.
After washing off the parts they were placed in a cast iron skillet and put in my kitchen oven to temper. They were placed in cold and the oven set to 425° for 1 hour. They stayed in the oven to cool.
Everything wouldn’t fit in one crucible, so I used both the sizes of crucible for everything but the lock parts and the triggers themselves (the trigger plate was done along with the hardware). The lock parts and triggers will be done in a few days. I plan to do these at a higher temperature to provide a greater depth of hardening.
So far I’m pretty happy for a first attempt. This could get addicting.
