Straighten steel

N.W. Gean

N.W. Gean

Joined
Oct 10, 2018
Messages
463
I've done countless hours of searching on this forum, and tried different methods, but none seem to work and I don't have a surface grinder. Using the magnet and flat platen made a nice finish but I don't believe the blank is any less warped. I tried hitting it against an anvil with a dead blow hammer and it didn't move. I'm using 1075 from admiral, which isn't annealed, so maybe that's why? I haven't used any of the 1084 I got from NJ steel yet. I wonder if that's easier to straighten.

Edit: I forgot to mention that when I try grinding warped blanks on my jig, the bevels are never even. That's why I'm so concerned about it.
 
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Use something flat to find the high spots, like the band saw table, drill press table, inspection plate etc.

Hit it on the high spots over the hardy hole until flat using a 2-3# solid hammer. It’s best to over bend then finish straighten. Look for twisting also. Untwist using a wrench and the vise.

Straightening is the hardest easy thing you’ll ever learn.

Hoss
 
There's absolutely no reason why you can't measure and quantify the straightness - all you need is a shim gauge set, which you can get for $7 on Amazon, and a straight edge. So instead of saying "Using the magnet and flat platen made a nice finish but I don't believe the blank is any less warped," you can say "my warp before flat grinding was 0.017", but after flat grinding it is 0.006. My platen has a 0.004" warp, so maybe that's why I can't get the knife flatter than 0.006."

As for mechanical straightening, don't think of it as straightening, think of it as counter-bending. If you're placing the knife on a flat anvil, you can't counter-bend. To counter-bend, you need to do something that allows the area hit by the hammer to move below the surrounding areas. The simplest, and most gentle, way to accomplish this is to place a piece of leather on the anvil - it will compress below the strike area.

I have explained my straightening processes several times in great detail if you check my comment history.
 
try the dead blow hammer on a wooden table that will flex. i use a 3/4" plywood bench top, not over a brace so it will flex. you need to whack the crap out of it. if you raise the blade up over 2 pencils or dowels at the ends and then hit it to get more bending power, you will end up bending too far. do not try that :)
 
If the steel is somewhat hard it would be a lot easier to straighten during heat treat or soften then straighten.
 
CollegeBladesmith said:
I've done countless hours of searching on this forum, and tried different methods, but none seem to work and I don't have a surface grinder. Using the magnet and flat platen made a nice finish but I don't believe the blank is any less warped. I tried hitting it against an anvil with a dead blow hammer and it didn't move. I'm using 1075 from admiral, which isn't annealed, so maybe that's why? I haven't used any of the 1084 I got from NJ steel yet. I wonder if that's easier to straighten.

Edit: I forgot to mention that when I try grinding warped blanks on my jig, the bevels are never even. That's why I'm so concerned about it.
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I always use wood under steel when I straightening .....this piece of leaf was bend , warp in any direction you can imagine .Now it is straight as arrow , magic is in wood , not in my ability . . ..
PS .It is quite thick steel 8mm taper to 5mm . ..:)
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DevinT said:
Straightening is the hardest easy thing you’ll ever learn.

Hoss
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Quoted for truth.
8 years in, and I'm still learning.
I can think of 4 snapped pieces of material offhand - 3 were hardened blades. (fortunately two were only made from files for fun)
 
Thanks for the replies. I was able to mostly straighten the knife this morning with a 3 point vice setup. It still isn't perfect but I'm afraid I'll just bend it the other way if I try anymore.
 
CollegeBladesmith said:
It still isn't perfect but I'm afraid I'll just bend it the other way if I try anymore.
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Intentionally bending it the other way, as an intermediate step, is actually a great approach that I use frequently. Your initial piece of metal is warped because it has coil memory. When you counterbend, you're fighting against that coil memory and it can be really easy to find yourself saying "a little more, little more, little more, TOO MUCH!"

So the trick is to first over-compensate and put a reverse bend in the steel, then work backwards to achieve final straightness. That way, the coil memory is working in your favor at the final stage of the process.
 
P.Brewster said:
Intentionally bending it the other way, as an intermediate step, is actually a great approach that I use frequently. Your initial piece of metal is warped because it has coil memory. When you counterbend, you're fighting against that coil memory and it can be really easy to find yourself saying "a little more, little more, little more, TOO MUCH!"

So the trick is to first over-compensate and put a reverse bend in the steel, then work backwards to achieve final straightness. That way, the coil memory is working in your favor at the final stage of the process.
Click to expand...

You my friend have straightened lots of blades.

Hoss
 
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