A blade's heat treatment (the process and result of hardening, quenching and tempering the steel) has been described by far more experienced knife makers than me as being the soul of the knife. The purpose of heat treating is to imbue the blade with just the right balance of hardness and strength so that it can take and keep an edge and function properly as a cutting tool. Prior to heat treatment the steel is simply too soft to be effective.
The stock removal process to shape a blade blank is, I guess, a largely mechanical process; that is not to say that it is easy - it isn't (or not yet anyway...!) but, it can all be seen with the safety-goggled eye and mistakes are immediately obvious. On the other hand, the important parts of heat treating take place at a molecular level to affect the physical and chemical state of the steel. at its most basic the process sees the steel 1) being heated to a very high temperature; 2) being cooled; and then 3) being re-heated to a more moderate temperature for a longer period.
With the basic principles in mind the challenge is, therefore, to work how the hell I can do this stuff...the answer, or at least part of it, is to make my own forge. As with many great projects this started with You Tube. I will use the 'Community' page on my site to recognise and thank those people who give their time and effort to share their skills and experience on You Tube - I have found this invaluable.
The basic forge design I have used is based around a gas blow torch and a chamber built with fire bricks.
The metal casing is aluminium held together only by the compression given by the steel studding. This is all that holds the fire bricks in place too as I wanted the forge to be fully maintainable in the event that any of the fire bricks broke. I drilled the main chamber with a hole saw. It has a drilled inlet in the site to fit the gas torch and it has a small vent at the rear.
My first attempt at using the forge was a failure on two fronts; first, it was the middle of winter, the gas bottle kept freezing, the torch sputtered a lot and it was difficult to maintain the heat; second, I didn't get the blade hot enough for long enough to full harden it - the lesson, don't bother trying to heat treat in a garage with no heating when it's sub-zero outside! However, I think the forge design is basically good and I have subsequently used it with success!