Newbie forging and HT questions

Z

Zanuha

Joined
Sep 27, 2010
Messages
437
So I'm going to forge a knife at school. I've ordered a 12-inch long, 1-inch wide, 6mm thick piece of spring steel from Brisa. I'm not that awesome at making handles, so I thought about making a knife like this one in Assassin's Creed 2:
AcII-sultansknife.png

What do I need to know before I start forging? Can I quench it in plain old tap water and temper it in an oven, and for how long?
Here are the specs of the steel provided by Brisa: C- 0.6 Si-1.60 Mn -1,0 Cr - 0.2 Heat treating: 780 - 830 C Tempering: 230 - 250 C.
Oh, and how far should I sharpen it before I HT it? Can I use a grinder or a belt sander with wood sanding belts?
 
Last edited:
I've never worked with that particular steel chemistry, but it looks forgable.
I'd suggest not hitting it once it gets down toward dull red....
Don't quench it in water. Any oil should harden a steel of that chemistry. I suggest a vegetable oil, canola or peanut.
Leave about 1 mm thickness to the edge when you quench, this will reduce the chance of warping. Do not swish the blade around in the quenchant, either.
Wood working belts are usually aluminum oxide, and work fine on steel. Do not let the blade get hot when grinding after the quench, grind without gloves after the quench and dunk it in water if it starts getting hot.
Read the sticky's at the top of the page, there is a wealth of information about heat-treating there.

Have fun!
 
Thanks. The thing I'm most concerned about is how I should forge the bevels. Do I hold both the knife and the hammer at an angle or what?
 
Zanuha said:
Thanks. The thing I'm most concerned about is how I should forge the bevels. Do I hold both the knife and the hammer at an angle or what?
Click to expand...
That is how I do it, tilt the blade slightly and work one side, and on the next heat I flip it over and work the other side, and repeat... Note that as you forge the bevel the blade will begin to curve away from the edge into a banana shape... To compensate for this, I curve the blank in the other direction a little before i begin forging the bevel, and it straightens out as the bevel is forged (it always needs a little adjustment to get the shape I want, but this precurve gets me in the ballpark).
 
If you want to see what will happen to the steel as you forge it, do a "prototype" from simple modeling clay. Make the blank the same dimensions as you piece of steel. Mash it carefully on a flat surface (wax paper helps with anti-sticking)with your fingers where you think you would hit the steel with your hammer. Take your time and watch closely what happens with the shape of the clay as you progress. Make sure you work both sides as you would during the forging process. You will see how the steel will move as you forge it. With the clay you can do it over and over until you figure out your game plan for the actual forging. It will shed a tremendous amount of light on what happens during the forging process without wasting fuel, time, energy, and steel.
 
When I do the bevels and it does the banana curve thing on the next heat I stand it on its edge and hammer it back to flat.
Cheers Ron.
 
If you work your bevels in conjunction with your distal taper you will eliminate or at least minimize any "banana" effect and accomplish two things at one time.
If it does curve, place it spine down on the anvil face and hit the top of the curve with a chunk of hardwood. You won't damage the blade edge by flattening or rolling it over and will still get the spine flat. An old shortened baseball bat works just fine. Do it quickly right out ot the forge for best results.
 
I'm not doing a distal taper. Will that eliminate the banana effect? Should I harden the whole thing or just the blade?
 
Forging+bevels=banana effect no matter how you deal with it , if you fix it with a wood bat or a hammer makes no difference both work well, key is to fix it before it gets to big, so fix it at each heat and all will be well.
Harden just the blade (the cutting edge is what needs to be hardened), you will never be able to drill a hole in the tang if you harden it, and the tang will break easier hardened, generally speaking with your first few knives.
The blade you want to make in your post has a banana curve to it anyways so with some luck it might come out right without much anti banana work. Cheers Ron. :thumbup:
 
With no distal taper forward toward the tip/point and rearward through the tang/handle section, the "banana" effect is going to be much more extreme than what the knife has in the pic. You are either going to have to forge in tapers or do a LOT of stock removal (if so why forge at all?). Play with the clay and it will become quite obvious.
If you do intend to forge out the tang to get the results in the pictured knife, do it before you forge the actual blade. You'll get needed practice and won't have the potential fo damaging the blade while you work at reducing the tang.
I hope you have fun with the project.

Not to be contrary Mungo, but with proper forging technique and hammer control working distal tapers and bevels at the same time, one can pretty much eliminate "banana" effect during the forging process. I agree with "fix it as you go", too many get too far before they try to correct things.....got to pay attention to the whole picture all the time.
 
Alright. The piece is only one inch wide, can I flatten it with the same hammer I'm forging with or do I need a special flattening hammer? How long should I temper it? Should I fully sharpen it before or after the temper?
 
180C is a heck of a lot warmer than you need it for quenching. Even room temp would be ok, just not ideal. You want it warmed up to a bit too warm for comfort but not so hot you can't stick a finger in it, to use an unscientific method. :) What you're doing by heating it up is decreasing viscosity and increasing the rate of thermal transfer when you stick the hot blade in. It's not like it doesn't work at all at room temp, but it works BETTER warmed up.
 
It seems like you should Google basic knife forging to get a feel for what you want to do, or visit somebody who does it to see how it is done.
Cheers Ron
 
nope, not if you have sufficient oil. I use a couple gallons and if I'm heat treating a few knives in a row there's just a couple minutes at most between blades and that's enough time for the quench tank to give up most of the heat I added. It's warmer, but still fine even after the second blade. I've only done three in a row a few times and didn't check after the third, I was too busy getting everything wiped down and inside for tempering.
 
You must log in or register to reply here.
Back
Top