Knife making questions (heat treating)

[Draven]

Howdy folks!
Well, guess what I found out?
Apparantly my dad has a blowtorch he's been hiding from me for several months because he:

didn't want me burning the house down

Parents, eh?
Well anyway, he's told me now, which is the important thing. He suggested using it to soften the tang on the Mora blade I'm putting a handle onto so that I can drill holes in it and pin it to the handle.

Anyhoo, the torch burns a Butane-Propane mix at around 1350degC. Would that be hot enough to soften the tang on the Mora?

Also, how should I stop the heat-treat on the blade being ruined?

Would it be hot enough to bring a fresh Carbon Steel blade to cherry red?

To soften the tang should I bring it to a cherry red and then let it cool slowly in the oven?


If it'll be a hot enough torch I should be able to start knifemaking a lot sooner than expected

Cheers folks!

 

[Ogri the trog]

Draven,
Heres my take on some possible answers but wait for some other advice as well, I've only been playing with blades for a short time and my ideas might be a bit off the mark.

Anyhoo, the torch burns a Butane-Propane mix at around 1350degC. Would that be hot enough to soften the tang on the Mora?!

It should be, so long as you can retain the heat in the area of the blade.

Also, how should I stop the heat-treat on the blade being ruined?!

Not exactly sure but something like a clay mask over the blade part to minimise the heat.

Would it be hot enough to bring a fresh Carbon Steel blade to cherry red? !

Again, should be so long as you can retain the heat.

To soften the tang should I bring it to a cherry red and then let it cool slowly in the oven?!

Probably - non-magnetic would be better I think, just check with a magnet on a stick.

If it'll be a hot enough torch I should be able to start knifemaking a lot sooner than expected
Cheers folks!

Theres plenty of other heat sources around Draven, open fires and barbeques to name just two. I keep saying that if Iron Age Man was able to work the material, then we should be in with a fighting chance.

ATB

Ogri the trog

 

[Draven]

Cheers mate

Theres plenty of other heat sources around Draven, open fires and barbeques to name just two.

Yeah, I do still want to try it sometime with an open fire, but I can't start a fire in my back garden because it's a Council House, and they'd probably have a problem with it With the torch I could either work something out inside the house, or if I can't come up with a suitably safe setup, then I would be able to use the torch in the garden.

I keep saying that if Iron Age Man was able to work the material, then we should be in with a fighting chance.

never thought of it that way! Very good point indeed!

 

[Ogri the trog]

Cheers mate


Yeah, I do still want to try it sometime with an open fire, but I can't start a fire in my back garden because it's a Council House, and they'd probably have a problem with it

But a barbeque running on clean charcoal would do the job. I mean the raw stuff, not the petroleum impregnated burn in the bag stuff.

ATB

Ogri the trog

 

[Draven]

Wouldn't I need some setup to pump oxygen into the BBQ to get a hot enough flame?

 

[Simon E]

Wouldn't I need some setup to pump oxygen into the BBQ to get a hot enough flame?

No, a fan or an old hair dryer would be suficcient provided you had a space under the coals to let the forced air in.

I have heat treated a few knives I made from a Nicholson file (Be careful with files, a lot of them are just case hardened and are usless for knives, Nickolson are made from W2) The actual hardening isnt a problem, but tempering it down from about 65Rc is)

Anyway, the reason for this post is to say to be careful about heating the tang, the reason being that a blades temper can be ruined after 200 degrees C and that I think you wouldnt be able to heat the tang sufficiently to soften it AND keep the heat away enough from conduction to the blade of the knife.

To really soften (anneal) you have to go to non-magnetic, which as it sounds is the point that a magnet will not stick to the metal anymore. In ny experience that isnt cherry red but more like Tangerine yellow/orange.

Anyway, I think that you could probably find a drill bit of sufficient quality and cost to get through 3mm of steel and dont concern yourself with heat.

Sorry for the ramble

 

[Tadpole]

Howdy folks!
Well, guess what I found out?
Apparantly my dad has a blowtorch he's been hiding from me for several months because he:



Parents, eh?
Well anyway, he's told me now, which is the important thing. He suggested using it to soften the tang on the Mora blade I'm putting a handle onto so that I can drill holes in it and pin it to the handle.

Why do you need to soften the tang? Do you just want to drill a hole or two?
If you have a pillar drill or can access one for about 10 minutes, and are willing to invest a few pounds in a couple of cobalt drill (8%) one pilot and one of the right size, you can do the job with a lot less fuss.
Axminster Tools sell both sets of cobalt drill and individual drills fully able to drill hardened steel up to 66-67 on the Rockwell hardness scale. (most mora/clippers are nowhere near that hard, the plastic handled ones being somewhere between 57 to 60 rockwell)
Mark the place using a hardened steel centre punch, then drill a small and accurate pilot hole of say 2mm and then the main hole (to find out what size pilot hole to use measure the web of the finished sized drill you intend to use and use a pilot drill slight wider than the web thickness) Use a relatively slow speed (150 to 300 rpm) and a cooling/cutting agent. You will be fine if you keep a slow and steady pressure.

 

[Draven]

a blades temper can be ruined after 200 degrees C

Really? I thought it had to be much hotter than that!

Why do you need to soften the tang? Do you just want to drill a hole or two?
If you have a pillar drill or can access one for about 10 minutes, and are willing to invest a few pounds in a couple of cobalt drill (8%) one pilot and one of the right size, you can do the job with a lot less fuss.

Yup, tis only to drill two holes. Unfortunately, I don't have a pillar drill, and the college I go to doesn't let us use the tools for anything other than what we're studying (Mechanics in my case...) so I won't be allowed to drill a blade... in fact I wouldn't be allowed to bring it in to ask.


To be perfectly honest, I'm not overwhelmingly bothered about this blade getting messed up. The whole process from dealing with the handle to the blade is intended only as a learning experience. It'd be nice to end up with a good, useable knife at the end, but I never really expected to to start off with. However, I have and will continue to learn valuable lessons which will help me in doing my next knife


Right, anyway, with that in mind, down to business...

Dad was confident (and if he's wrong, I'll be able to get him to buy me a new blade... ) that the heat-treat on the blade wouldn't be ruined by heating the tang. Sooo we gave it a go... got the blade to non-magnetism without any bother.
After numerous mess-ups (apparantly our power drill has a dodgy switch... I had set it to drill the right way and it was going reverse... led to the drill bit being dulled, etc) I managed to drill one hole without too much bother. The second was a bit of a different story. After a very long time and a broken drill bit, I've gotten a small pilot hole, but I can't get the larger bit to widen it. Not getting metal shavings, not even getting metal dust I heated it to non-magnetism again and tried again, but still nothing. I'm not quite sure what I'm doing wrong, but I have discovered one thing: If the tang was supposed to be pinned in place, it would have holes in it Now the tang seems as hard as ever...
Right, so anyway, I decided to put a pin the one hole anyway, at least it would add a bit of strength... so I drilled the wood. Haven't got a clue what happened there! There must have been a sudden change in density somewhere where I was trying to drill, because the drill shifted off to one side suddenly and I was left with a hole at a 70 degrees angle Which, I suppose, I deserve, for not clamping the scale. Like I said, all a learning process...
Anyway, I straightened the hole and put the pin in anyway. I'll fill it in with somethingorother and then just finish the knife. Looks like I'll be getting a knife out of it, just a knife with no value other than sentimental
Which, I suppose, I expected. At least I learned a few things:

I'm NEVER going to try softening a hardened tang again.

Always clamp everything when drilling. And don't be so clumsy with a drill.

I need to listen to the good people that know better than me

And also, I need to always remember that even if it's my dad putting the blade in the oven, it's my job to remove the electrical tape that was stopping the end of the blade getting scratched by pliers.

The most basic lesson I learned was that drilling a tang is probably more effort than it's worth and I'll mess it up anyway
So next knife will definitely be a stick tang. Held in with epoxy!

I thank you very much folks, and I'll remember this thread next time I have to soften a hardened steel