Taking out warps.

F

Forgedog

Well-Known Member
Ok sort of noob questions here.
I have a few blades with warps...

Ive NEVER been good at straightening blades.

I know theres A LOT of info and ways to do this, but ive been having little luck.

The steel stock I have 4" x 4' came from the factory with a warp. 1095 80crv

Now it sits there because idk what to do with it.

I usually heat it up in my heat treat oven then I either hammer it or bend slowly in a vise or make a bending jig with a couple pieces of round bar.

The problem is... When I try to correct the bend I tend to make it worse in other areas.

Im considering some form of "quench plates" ? Or idk... Can I plate a blank and HT with the plates on?

I just need a simple way to straighten the whole thing evenly.

Also my other issue is how to work the adjustment into the heat treat process.
Like... Does heating to straighten effect the HT? Do I have to anneal or re treat after?

What if its a factory blade warp 1095... I have an old ka bar thats been kicking around that arrived with a factory warp.

Thanks.
 
Straightening your piece of steel will not be the same as straightening a blade warp. If I had it and wanted to use it, I would forge it. What you are wanting to do is akin to trying to straighten a leaf spring. It usually takes several forge heat cycles and hammering it flat to get it straight.
 
If you are forging with it, I wouldn't worry too much about a bend in the piece of metal. You will have to straighten as you forge anyways. If you are doing stock removal, that is a different story. You can always grind your steel to get it straight, but you lose a lot of metal that way. There's a lot of variables here to discuss. If you bend the metal, then only do stock removal, there's a good chance your blade will warp during the quench if you don't normalize and stress relieve the blade before hand. Any time you bend metal, you have realigned the grain boundaries, and introduced stress in the cross section. If you don't relieve those stresses, they will normally present themselves during hardening. You can always straighten a blade after hardening if it is warped during your second tempering cycle also. There are a lot of posts on how to do this as well.

Without knowing how you are making a knife, it is hard to give specific advice.
 
Mostly stock removal.
The blades dont often warp for me in the HT process. Mostly its from "pre warped" factory steel.
Ive tried grinding and it does lose a lot of material.
Ive tried bending the steel flat bar back into shape prior to cutting the blank... But tend to make it worse.
I figure the warp is from the process of shearing the steel in the factory.
 
Ok. That helps. Unfortunately, in my opinion, this is kind of the worst case scenario. Stock removal with a bend already in the metal is kind of a killer. Straightening a 4 foot piece of steel is a huge challenge, so I think you should probably focus on trying to straighten each individual blade as you cut them out. However, after bending, it is important that you then normalize and stress relieve the blade before you start grinding. After doing this, you are going to lose any annealing that had been done on the metal, so it is going to be harder to machine, so I would also recommend annealing the blade. You are basically on the edge of the forging process at this point. There are others on here with much more experience than I have who may have better suggestions.
 
Thanks! that actually gives me some ideas.
Tbh... Iv never tried normalizing, stress relief or annealing because it seems a bit complex... Salt pots and such I believe?
I do have a paragon heat treating oven... Is there a process to do these steps for 1095 and 80crv with just the kiln?
 
Forgedog said:
Thanks! that actually gives me some ideas.
Tbh... Iv never tried normalizing, stress relief or annealing because it seems a bit complex... Salt pots and such I believe?
I do have a paragon heat treating oven... Is there a process to do these steps for 1095 and 80crv with just the kiln?
Click to expand...
It's actually a lot easier with a heat treat oven. You can be super precise with your temps. There's a whole section on this forum on the heat treating of different steels. Now, the annealing gets a little more complicated depending on if you want to do lamellar or sphearoidal annealing.

You can start a long discussion and arguments on the process of normalizing and stress relieving. The easy way is to heat to 1600 and air cool. Do that 3 times. I won't get into the discussion points of reducing temperatures here.

The easiest way to anneal is probably to heat to 1500 and then put it into a bucket on an insulator such as vermiculite or pelatized gypsum. Some people even use wood ash. This will make it cool very slowly, and create a lamellar annealed pearlite microstructure. Sphearoidal annealing is better, but more complicated. Kevin Cashen is the expert on these processes. I would recommend studying his website and postings.
 
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