Herb, I am not familiar with what type of steel is used in TS blades. And at 3/16" thick it may take more heat than a Bernzomatic propane torch produces to get it to a dull cherry red hot. I use O-1 (oil hardening) tool steel. I did use an old lawnmower blade once, and it was 3/16". To get it hot enough required 2 Bernzomatic propane torches. I quench at dull cherry red into canola oil in a can...after cooling, I anneal it in our kitchen oven set at 400 degrees for about 45 minutes (to a dark straw color).
You want to grind the shape of the blade to the finished shape before you harden the iron, and can be done with a file when needed. Once you have hardened it with the torch, you then polish it using sandpaper to remove the excess carbon and make it shiny (reflective). Being reflective...when you put it in the oven you will be able to see the color change. Remove it from the oven when it reaches a dark straw color and let it cool to room temperature. After that you can sharpen the iron to it's keen edge.
Using this method will not work with mild steels. There is no carbon in the steel and it must be added to make the steel tougher. A blacksmith uses coal to add the carbon during the heating process to add the carbon necessary, and that is what makes the steel tough. Of coarse this is just a basic overview.
Last edited by gmercer_48083; 03-10-2019 at 08:51 AM.