Heat Treating For The Hobbyist Knife Maker

Ethan Allen
 
 
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There’s a growing number of people that are getting used to knives as tools again, just like our grandparents did, especially when off the beaten track and in the woods. We’ve had a few knife making type articles published on Outdoor Revival over the last few months so we thought it would be a great idea to help you along with heat treating any blade you make.

I’ve made a couple of knives and I know that the heat treating can be a scary concept but it’s a simple process as Thomas from British Blades shows us below in this step by step article.

Ok. This is a very basic guide to heat treating your blades if you are a hobby or amateur maker.

 

First of all, as stated in the thread above, I have no idea what the steel is But this particular project aside, the methods for HT are the same I use for all the steels I use. O1, 1080, En9, W2 and so on. This is NOT for more complicated steels like D2, which are steels of the devil
This covers simple oil quenching and not clay quench or water quenching.

Right. First of all, above is the blade sent to me by ‘Everything Mac’:

When you make a blade ready for HT’ing, leave at least half a mil of an edge thickness. Don’t put any kind of edge on it. A sanding to 240 odd grit on the blade will be fine. Degrease the blade with white spirits or similar and set aside while you get your forge ready.

This is the forge I’m using:

It was made from a gas canister. Cut with an airflow tube attached and an air spreader on the surface of the inside base.

 

Airflow tube from underneath:

And looking down into the pit, you can see the plate with holes drilled. This spreads the air as it comes out into the coals. (I need to clean it a bit, some holes are full of gunk)

Now, just fill the pit and get some charcoal burning Burn them till they are really hot, then add more. This can take a while, so don’t expect a roaring fire in 5 minutes!

I used to use an old BBQ. Just the same principle. I had cut a hole in the base, stuck in a tube, and used a paint tin lid with holes drilled as my airflow spreader:

While we wait for the fire to get going, here are a couple of methods for using bellows to get the heat up. You need bellows to blow air into the coals, which make them hotter.
This is a large hand pump which will blow air on the up AND down stroke:

I have used these loads of times. Make sure you don’t hold the nozzle too close that it melts You just point the nozzle at the coals and pump, nice and smooth, don’t go like the clappers or you will end up knackered before your steel is ready, or injure yourself. (note on safety! Always wear gloves, gauntlets, specs, apron, etc….)

The method I mostly use is the hair-dryer one. A hair-dryer taped onto a hoover hose

Like so:

The hair dryer gets turned on to the lowest setting. This is always enough air to fire up your forge.

Now, the coals have been burning a while. They look quiet….

But when you turn on your bellows….

Note the oil sitting near enough the forge that i can quench quickly, and the magnet even closer.(Speaker magnet sitting on the wood, second pic up) You MUST make sure your steel is NON magnetic before you quench it. So have it close to both your forge and you oil for obvious reasons

Ok, now we have fire. We have a blade to HT, so now all we need to do is get the oil ready. And get your kitchen oven pre heated! Between 180 and 200c. I use gas mark 4.5.
I stuck in a piece of mild steel round bar to heat up.

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