Knife blanks

[elkriverfab]

I cut several knife blanks out today.
Here are two.

I have never cut saw blades before.

I was surprised that they were not very hot after cutting like most of the steel I cut.
I guess the size of the saw blade dispersed the heat????

Don't know why that was the case.

I also can't believe how hard they are and I also cut a blank out to see if it was going to bend or be brittle.
I could not bend it and I can't get it to break.

Does anyone think I will have to re harden these things?

I don't see why I would have to.
I also sharpened one of the test blanks to see how it took an edge, very nice.

I am just guessing it was the quality of steel.

We have had this old blade here at the house for over 40 years (28 inch round).

If anyone has any ideas on having to harden them, please let me know.
I think since it was a saw blade it had already been hardened and the heat did not come close to changing the metal.

Thanks.

[bigj121]

Those are very nice. I remember reading on this forum how to heat trat. Someone gave very detailed intructions. Do a search, I am sure it is still here.

I want a plasma or real laser again!! I sure do miss doing stuff like this!!

[WSS]

Here is a good read.....

http://www.crucible.com/eselector/gener ... part2.html

WSS

[plain ol Bill]

The knives should be a simple steel to heat treat really. Heat the blades to the point a magnet will not stick to them (that should be somewhere from 1450 to 1550 degrees) then dunk them in some mineral oil to quench. The mineral oil should be warmed to somewhere in the range of 120-140 degrees before quenching. Leave in the oil until cool enough to touch. At that point they are going to be very brittle. Put them in a toaster oven at 400 - 425 degrees and leave them for an hour. Let cool and repeat the toaster oven. The toaster oven will temper the steel back to a usable material. When sharpening do not let the material get too hot. If it turns blue it is not good anymore and will have to be re-heat treated.

[Scratch]

Bill, you say temper at 400-425 for an hour. I was heat treating some gun parts made from 4130, and I read anywhere from 300 to 800. I know there are experts "all" over the net, but you make knives right? I didn't know what to do so I heated my oven to 500, stuck the part in, let it bake for about 30 minutes, then as I pulled it out, I hit it with a propane torch to jump it up a little more. Do you think I'm ok, or did I ruin anything.

I did harden to non magnetic and quenched in oil. I wire brushed all the scale off before I tempered but the whole thing turned kinda purply grey...

[WSS]

Drag a new/sharp file across it lightly, if the file feels like it is slick and slides easily without grabbing, then it is probably hard. Did you have a target hardness? Do you know the type of steel it is?

WSS

[elkriverfab]

WSS,

I don't know what kind of steel it is.
It was cut from a 28 inch round wood saw blade.

My grandfather had the blade for at least 40 years wanting to build a 3 point PTO saw for the tractor.

He never built one because he didn't want the thing sitting around for someone to kill themselves with it

I did run a file over some of the knife blanks to help clean up a few areas and it is hard steel.

The file would not even touch it.

A flap disc however did a better job than the file.

To be honest, I am wondering if I am going to have to soften the metal to drill holes and shape (grind) the blade.

Like I sad, this steel is hard. If I am able to belt sand the bade in the state it is in now I would not worry about heat treating it at all.

I think I can belt sand to shape it but drilling may be an issue.........

I used a bench grinder to do some handle shaping and I had to spend some time doing it. The steel is hard.

If I can belt sand them I have no doubt they will hold an edge.

I have heard so many people talk about heat treating certain steels for knives and understand completely why you do it but the blanks from this round blade is better than many knives I have bought (only down side is it's not stainless).

If I can drill it I will probably just keep it how it is??????

I was wanting to make a few knives for gifts.

Any help would be great.
Thanks.

[plain ol Bill]

It not being stainless is not a downside (just from my point of view anyway). Go ahead and grind an edge on it - then like WSS mentioned touch it w/ a file. If the file skates you are hard enough, if it bites in then harden and temper it.

Scratch I think you went way too high a temp to get a good temper for a knife blade. But when you get down to it it all depends on what type of steel you are working with. When trying to give advice on an unknown steel I try to stay in the middle of the road on how to proceed. Lets face it - the steel is the body of a blade - the heat treatment of it is the SOUL of a knife. I have worked with most all of the steels used for knives at one time or another and do all my own heat treatment. My favorite is still high carbon steel - simple, very effective, easy to sharpen and cuts like an old womans tounge.

[elkriverfab]

Plain Ol Bill,

Should I cure the blade like cast iron?

This old saw blade has been setting indoors for years and has acquired a real nice look to it.
Not really rusted but more of a patina look.

Once I grind the edge I know it will need to be polished.

Is there a way to cure it back to a natural patina look once the edge is on without having to let it set for another 40 years ?

I thought about polishing it up to a high shine and may do so but I sure like the weathered patina look it has now.

I was thinking the road runner blank would look nice with some buffalo scales or maybe camel bone (Dark tone).

Thanks again.

[WSS]

Here are some pics of my heat treat set-up.

It can get to 2100f and can be used for drawing/tempering. It is sized specificaly for knives up to 20" long. It works good. I use argon with a flow meter turned on to 1 or 2 cfm to purge oxygen out of the chamber to help with scale, I also use "tool wrap" which is a inconel foil and make pouch to put the blades in, I usually drop in a piece of paper or something that will burn quick to eat up any oxygen in the pouch. The steel tube has a plate welded to the bottom of it and is filled with queching oil. I use a set of tongs to get them in quick.

Hope there is some useful info here.

WSS

[bigj121]

Thanks to all for all the helpful information!

[plain ol Bill]

Hmm - I had a long post I thought I had added about heat treating but it wound up in never-never land I guess. I likely pushed the wrong button - again.
Elkriver wish I could help about the patina but I don't have much experience with making one look old. You might try mustard. That will help darken metal.

[oldsoulmetal]

blanks look awesome. don't know if you can recover the patina. my guess is the patina is a combination of burnt tree sap and age. them saws get hot when cuttin so i know the resin can coat the blades. i have had some success with heating the blade up to a dull cherry red then quenching it in oil. it leaves a black coat on the blade. you may try metalfx and see what he says. he may have a chemical recipe that will work.

[elkriverfab]

oldsoulmetal,
Thanks.

I will polish out several blanks to a nice shine but I sure like the weathered look.
I would like to keep one weathered.

I may just add some sort of patina to one of the blanks. one is going to be a gift and not a knife that is going to be used in the field (display only) so a patina may work.

I like to use the easy torch product with their copper product.
If you apply it just right you can get a deep leather look.

I am interested in looking into the Steel FX products to see if he offers something similar.

We will see, after getting into it, I may just polish them all!
They will last longer that way and oil can be applied to help keep them from rusting.

One advantage to that is, the display can actually be used too.

[WSS]

When you say polish, do you have a grit you will go to? Will you try to get all the scratches out? A polished knife (no marks, pink rouge) takes a good five times longer than a 400grit and bead blasted knife does (I like my bead blaster )

One option for a weathered look might be the etcher used for damascus. I cannot remember the name, but it is the same stuff used on printed circuit boards and available at radio shack. You dilute it 50/50 with water and start with a quick dip to see if you like it. The longer it is in the more it eats the metal. No longer than five minutes I would say.

WSS

[plain ol Bill]

Ferric Cloride is what WSS was referring to.

[tek]

ferric chloride will give you a patina similar to this one.


Brad