Question about knife im going to make

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mihaelx

Joined
Dec 22, 2023
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Hello, this is the knife i plan to make out of O2 steel with a hidden tang. The blade is 15cm (about 5.9"), the handle is 10cm (about 4"). Now my question is, do i make the hidden go 1cm deeper or is this just fine? And if i put a brass pin, should i put it exactly in the middle of the tang, or wherever i want? (its gonna be epoxy glued)
https://imgur.com/a/tdUm8PY
sorry for blury pic, it was better on phone haha
 
mihaelx said:
Hello, this is the knife i plan to make out of O2 steel with a hidden tang. The blade is 15cm (about 5.9"), the handle is 10cm (about 4"). Now my question is, do i make the hidden go 1cm deeper or is this just fine? And if i put a brass pin, should i put it exactly in the middle of the tang, or wherever i want? (its gonna be epoxy glued)
https://imgur.com/a/tdUm8PY
sorry for blury pic, it was better on phone haha
Click to expand...
Use the Golden ratio to choose a location for the pin. 3 to 5 is close. If you are not familiar with the term, give it a Google. I've used this a good deal when sizing blades and handles. Nice looking knife there. Fred
 
Fred.Rowe said:
Use the Golden ratio to choose a location for the pin. 3 to 5 is close. If you are not familiar with the term, give it a Google. I've used this a good deal when sizing blades and handles. Nice looking knife there. Fred
Click to expand...
That's cool Fred. I'm designing a Bowie with a 7.5" blade. If I set the handle at 4.6" which is pretty reasonable, I'll be right on the money.
 
As a added cheat, if you type in golden ratio caliper into Amazon you get dividers intended for aestheticians that have a extra center piece that shows the correct spot. Center punch, flip 180° and do it again. Super simple drill spots that don't look like crap. (until you drill a little off north to south) or maybe that's just me
 
aareeyesee said:
As a added cheat, if you type in golden ratio caliper into Amazon you get dividers intended for aestheticians that have a extra center piece that shows the correct spot. Center punch, flip 180° and do it again. Super simple drill spots that don't look like crap. (until you drill a little off north to south) or maybe that's just me
Click to expand...
I'll have to pick one up. Sounds like a very useful tool. Fred
 
They are really handy drafting tools.

You get them from beauty supply stores and online as "Eyebrow measuring caliper tool".
Yep, they are used for drawing and tattooing eyebrows on people. Eyes and facial spaces fit the golden mean.

Those dividers are also very useful for placing and sizing the eyes in painting and carving faces.
 
mihaelx said:
Also another question, when heat treating, do i do the whole tang also or?
Click to expand...
Most people do, but then they usually temper it back to thread it, drill the pin hole, etc. If you can't do the tang, i don't think you need to sweat it.
 
I always find that i quench the tang because it's easier to stick the entire thing into the quench. Keeping the tang out is just fiddly.
Then i draw the temper back later
 
mihaelx said:
Also another question, when heat treating, do i do the whole tang also or?
Click to expand...
If you do not immerse the tang in the quench oil, there is a distinct chance of fire. Have a lid and fire extinguisher nearby.
Best to quench the whole thing and temper the tang back with a torch.
 
Fitzo has the main point of full quenching a blade.

If the hot blade and hot tongs don't go all the way under the surface of the oil quickly, it will vaporize the oil and the vapors will ignite.

On shows like FIF they deliberately create this effect. In a real forge, you do everything you can to avoid it. Besides the startling effect of a puff of flames in your face there is a real worry of singed hair/beards/eyebrows and anything flammable above the quench tank could catch fire. This is one of the several reasons you need a sufficient volume tank for quenching blades. The tank should hold at least two gallons of oil, and be at least 4" deeper than any blade you want to quench. Also, you want at least 2" of air space above the oil to the top of the tank. An overflowing tank is the cause of many shop fires. 4" top space is even better.

How to deal with a flare-up:
Everyone will eventually stick tongs that are too hot or a too long blade to fully quench in their quench oil tank. If the tank has enough depth, push the blade and tongs all the way down under the oil. This usually stops the flame in a few seconds.
If the flames don't go out, or the flames are increasing, DON'T pull the blade out. That just makes a much bigger flame with dripping and burning oil falling on the floor. Instead of pulling it out - LET GO of the BLADE with the tongs and pull the tongs out, let them drip over the tank for a few seconds, and lay them on the anvil while you cover the quench tank with the lid. Problem solved and lesson learned. When the tank has cooled off fish the blade out with the tongs or a magnet and continue on with things.

TIPS:
A really good size quench tank is 6" wide by 24" deep and filled with 22" of oil.
It holds about 3 gallons of oil. It can be made from a section of 6" pipe or from a cut off large oxygen or other gas cylinder. Defective cylinders are often free at your welding supply if you tell them why you want it. If you need a sword tank this is by far the simplest way to make a 36 to 48" quench tank.
Take off the valve with a big pipe wrench (they might do it for you if you ask) and fill the tank with water. Drain and then cut to the depth you want with a metal cutting band saw or if you have to, with a hack saw.
Make a snug lid for it to keep stuff out and stop any flare-ups. An old kitchen pot (or pot lid) big enough to go over the tank works just fine. If your quench tank stays outside, place a heavy object on the pot/lid when not in use to keep it from getting blown off or pushed off by animals.
Welding the tank to a 12" round or square piece of mild steel, a large barbell weight, a big gear or pully from a crane, or any larger enough object is a good way to prevent the tank getting knocked over. Welding handles on the side of the tank and on the lid is also wise. A large tank full of oil that is welded to a 50# barbell weight is heavy!
 
Stacy E. Apelt - Bladesmith said:
Fitzo has the main point of full quenching a blade.

If the hot blade and hot tongs don't go all the way under the surface of the oil quickly, it will vaporize the oil and the vapors will ignite.

On shows like FIF they deliberately create this effect. In a real forge, you do everything you can to avoid it. Besides the startling effect of a puff of flames in your face there is a real worry of singed hair/beards/eyebrows and anything flammable above the quench tank could catch fire. This is one of the several reasons you need a sufficient volume tank for quenching blades. The tank should hold at least two gallons of oil, and be at least 4" deeper than any blade you want to quench. Also, you want at least 2" of air space above the oil to the top of the tank. An overflowing tank is the cause of many shop fires. 4" top space is even better.

How to deal with a flare-up:
Everyone will eventually stick tongs that are too hot or a too long blade to fully quench in their quench oil tank. If the tank has enough depth, push the blade and tongs all the way down under the oil. This usually stops the flame in a few seconds.
If the flames don't go out, or the flames are increasing, DON'T pull the blade out. That just makes a much bigger flame with dripping and burning oil falling on the floor. Instead of pulling it out - LET GO of the BLADE with the tongs and pull the tongs out, let them drip over the tank for a few seconds, and lay them on the anvil while you cover the quench tank with the lid. Problem solved and lesson learned. When the tank has cooled off fish the blade out with the tongs or a magnet and continue on with things.

TIPS:
A really good size quench tank is 6" wide by 24" deep and filled with 22" of oil.
It holds about 3 gallons of oil. It can be made from a section of 6" pipe or from a cut off large oxygen or other gas cylinder. Defective cylinders are often free at your welding supply if you tell them why you want it. If you need a sword tank this is by far the simplest way to make a 36 to 48" quench tank.
Take off the valve with a big pipe wrench (they might do it for you if you ask) and fill the tank with water. Drain and then cut to the depth you want with a metal cutting band saw or if you have to, with a hack saw.
Make a snug lid for it to keep stuff out and stop any flare-ups. An old kitchen pot (or pot lid) big enough to go over the tank works just fine. If your quench tank stays outside, place a heavy object on the pot/lid when not in use to keep it from getting blown off or pushed off by animals.
Welding the tank to a 12" round or square piece of mild steel, a large barbell weight, a big gear or pully from a crane, or any larger enough object is a good way to prevent the tank getting knocked over. Welding handles on the side of the tank and on the lid is also wise. A large tank full of oil that is welded to a 50# barbell weight is heavy!
Click to expand...
thanks for tips stacy, i heat treated the blade this morning. Its hard as shit, however, the edge chiped all over, as if i overshot the temperature in my homemade forge. What does this mean? Did i fuck it up?
 
Hard as "poo"- did it skate a file?
When did it chip? right out of quench before tempering? Untempered blades can be brittle as glass.
Did you run any tempering cycles on the blade before "testing" it?
Is it possible that the chipping is just forge scale flaking off?
Also you may have ground your edge too thin before heat treating. Old saw forge to Nickel(thickness) grind to Dime (thickenss) before heat treat
 
Last edited:
oldschool45 said:
"Hard as shit"- did it skate a file?
When did it chip? right out of quench before tempering? Untempered blades can be brittle as glass.
Did you run any tempering cycles on the blade before "testing" it?
Is it possible that the chipping is just forge scale flaking off?
Also you may have ground your edge too thin before heat treating. Old saw forge to Nickel(thickness) grind to Dime (thickenss) before heat treat
Click to expand...
It skates off, chiped right out of forge
 
Did it have chips on it straight out of the quench or from testing it with the file or chopping on something?

My best guess (I'm still under 30 knives made) is you probably ground it too thin before heat treating and it got a bit too hot in the forge.
I'd temper it and see if you can salvage the blade. I once turned what should have been a competition Chopper into the carving knife I used at my wedding because I overheated the blade while heat treating.
 
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