How should knife look before heat treat?

Pedro G.

Well-Known Member
What should my knife like steel look like before heat treat?
(I would be using charcoal in a crummy brick forge, it would be 1084 steel 1/4" thick. I want a mirror finish after alls said and done.)

Specifically:
1) Should I have drilled the wholes already?
2) Should I give it a mirror finish before heat treating? If it's a waste of time then to what grit?
3) Is there any part of the blade which doesn't need to be sanded and polished? (Limited sandpaper *More than enough to do the job but when it comes to higher grits 1000-2000 I don't have much*)
4) Should I make the cutting edge yet? (It is very think and flat I have not given it an edge yet.)
5) Anything else you could tell me.

Thank you very much.
-Pedro G.
 
Last edited:
1) Yes...drill your holes.
2) No...Sand to 220 since you'lle be cleaning scale from your crummy charcoal forge.
3) You should clean up the whole blank after dunking it, at least to clean metal.
4) No....you'll hurt yourself/ burn the edge in heat treat.
5) Start working your blank to the final finish and thickness that makes you happy. (assuming you have a grinder. If not.. get it as close to finished dimensions as possible before the dunking ceremony.

Rudy
 
When you say final finish what do you mean?
Should I get the big scratches out? How do I do that if my grinder doesn't fit in the small spaces and handsanding doesn't seem to do much.
 
Flat bar sanding works miracles. Thats a 12 or 15 inch long piece of 1/4 inch by inch to inch and a quarter wide. Start with 80 grit paper wrapped around the center 4 inches of the bar. Stick a refrigerator magnet on the bar to hold the paper in place, clamp the blade in your vise and sand away. This is a great way to get all your sanding lines running longways. Go 80 120 then 220 before heat treat.

Fred
 
Yeah......
What Fred said.

You need to have some perseverence, we all go through basicly the same procedure.For small spaces a simple dowel with sand paper works. There isn't any one tool or combination of tools that will perform every task neccesary without using some elbow grease.....it's just a fact of life.
Most times after heat treat and clean up on the grinder, you'll actually have to touch your work physically to get it where you want it.

Rudy

Rudy
 
One thing to add, the thickness of the edge should be left thicker than what you want to end up with, you will need to clean the decarb off of the blade and that can be prety thick. So I like to leave my edge thickness on carbon steel around
.030-.040" thick before heat treat, this also helps to prevent the edge from warping and cracking, and leaves plenty of thickness to clean up. If you are using a grinder after heat treat, be carefull not to over heat the edge as you grind, go light on the pressure, and if you have a variable speed, slow it down, and dunk in water after each light pass. And you will need to do alot of hand sanding like Fred and Rudy said.
 
Since you asked about hardening 1080/84 steel in a different thread I'm going to assume that you will be doing this yourself. I use a homemade charcoal fired "forge" made from a large coffee can. A downside to using charcoal is that I often end up with what look like little blisters on the blade. It's quite frustrating to spend a lot of time and energy sanding a blade nice and smooth and then have these bumps appear. On the other hand, they do add a measure of "character" to a blade in the same way that leaving hammer marks on a forged blade adds character.

If you're using a gas type forge you will have less to clean up on the blade after quenching and no bumps.

I use canola oil for a quench, because I'm cheap and not doing this professionally, just for fun.

Practice on some scraps or small pieces of your steel.
 
Since you asked about hardening 1080/84 steel in a different thread I'm going to assume that you will be doing this yourself. I use a homemade charcoal fired "forge" made from a large coffee can. A downside to using charcoal is that I often end up with what look like little blisters on the blade. It's quite frustrating to spend a lot of time and energy sanding a blade nice and smooth and then have these bumps appear. On the other hand, they do add a measure of "character" to a blade in the same way that leaving hammer marks on a forged blade adds character.

If you're using a gas type forge you will have less to clean up on the blade after quenching and no bumps.

I use canola oil for a quench, because I'm cheap and not doing this professionally, just for fun.

Practice on some scraps or small pieces of your steel.

The blisters are probably where the blade has overheated because of the charcoal. I had the problem a lot when I forged using coke.

Fred
 
Right now i'm using a carpenters pencil and i'm wraping a couple of inches of sandpaper around that. It's worked ok. But it's taken me a good 6 hours now and i'm not yet at 220 grit :/ I also have to put a ruler under the tip because if I leave it hanging and I press down on it it bends. I tried going 120 grit but it seemed to leave deep cuts in the steel so I took it down to 100 grit hand sanding and i'm doing 150 grit. Then I will try 220.
 
What should I do since the tip and about 1 Cm down the edge from the tip seem to be at edge thickness... And when I tried to sand it on my grinder so it would flatten it the knife somehow jumped back and the tip bend really badly.
 
I'm trying to get a smooth mirror finish though.

When I start the clean up what grit should I start at?
 
Mirror finish; not worth all the work it takes. One scratch and the illusion is gone. Scotchbrite is quick easy and looks good.

Fred
 
I still want to go for it. I love mirror finish. And it doesn't seem all that bad besides trying to get all the scratches out. But my blade is ready for HT right now. I got all the scratches out from the blade and ricasso area. From all the edges and the indent. (Was a huge pain in the butt but It worked).
While i'm waiting to get some money for charcoal and oil i'm trying to get the bolsters ready since I just recieved my brass flat bar. But I have a huge problem and I just waisted 3" of brass and it makes me feel pretty guilty :p. I can't drill the holes perfectly even with the knife. I have no idea how to get the marking perfect and when I do my holes just don't end up perfectly matched. It seems like my bits are bending or something because I think i'm getting it right. But I ended up ruining another nice piece.
I use a drill press.

-Pedro G.
 
Put a 2x4 in the vise edgewise and use a 4" or 5" c-clamp to fix the blade down to this. It supports the blade to keep it from bending (you might have to use shims to make this part work) and will keep you from impaling yourself on the blade, which is easy to do. If you don't do something similar to this, you should at least take the blade out of the vise before you walk away, leaving it sticking out is an accident waiting to happen.

You want something more ridgid than a carpenters pencil for a sanding stick, you want to be able to put pressure on it without causing it to flex or you will be all day trying to get rid of the scratches in the middle of the bevel, and will end up convexing it by the time they are gone. 3/16" or 1/4" steel or brass bar stock with the corners rounded off a little works for a sanding stick.

I do sort of the opposite altogether, and use a granite block fixed to my bench with a clamp setup to hold the sandpaper down. I do most of my hand sanding by moving the blade across this, but most makers seem to prefer the other method of fixing the blade and moving the abrasive.
 
I bought a vacuum vise form HF and I drilled holes on the corners and screwed it to the table. (I did a very sloppy job... It wobbles its fair share.) Anyways the vice can go 90 degrees and it already comes with some rubber pads for the jaws and it holds pretty darn well! It was only 15$ too. I put a flat piece of alder twice the blade length under the blade when I hold it but since the bevel is centered on the blade it floats and when I press on it firmly enough it bends. So I put my ruler under it but it was very uncomfortable and i'm pretty sure I sanded off the 7" mark :p
I ended up hand sanding the edge down some. Atleast now it resists bending a little more.

Wouldn't the be a little heavy? I understand what your saying though. I will give it a try.

It sounds like a more uncomfortable method when it comes to moving (Preferance) but I can definatley see it making the job quicker.

-Pedro G.
 
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