Photos Straightening Hammer (JT's design)

N.W. Gean

N.W. Gean

Joined
Oct 10, 2018
Messages
463
Hello all. I heat treated a couple knives this past week, and have been dealing with warps. The 1st knife started with a bow of about .009 in the tang, and I was able to shim it and temper out most of the warp, but was left with a nasty curl of about .005 at the pommel. Nothing was working there, not the torch method, not the 3 point jig, I mean nothing. So this morning after doing some reading on the forums about JT's straightening hammer I decided to try building one. A $5 ball pein hammer and an old tap laying around the shop later and here it is:
https://imgur.com/a/bgZPDUF
bgZPDUF

bgZPDUF

To make a long story short, the blank is almost dead flat from tip to tang. I feel bad for not buying one but 50 bucks is a lot for me right now. Thanks for the design JT!

Edit: I seem to be having a lot of issues posting the photo so I added the link. Apologies for not being able to make that work.

Link(s): I'm adding these for the source of the idea

https://www.bladeforums.com/threads/straightening-blades.1676557/page-2
 
Last edited:
N.W. Gean said:
Hello all. I heat treated a couple knives this past week, and have been dealing with warps. The 1st knife started with a bow of about .009 in the tang, and I was able to shim it and temper out most of the warp, but was left with a nasty curl of about .005 at the pommel. Nothing was working there, not the torch method, not the 3 point jig, I mean nothing. So this morning after doing some reading on the forums about JT's straightening hammer I decided to try building one. A $5 ball pein hammer and an old tap laying around the shop later and here it is:
bgZPDUF

bgZPDUF

To make a long story short, the blank is almost dead flat from tip to tang. I feel bad for not buying one but 50 bucks is a lot for me right now. Thanks for the design JT!
Click to expand...
Your images aren’t showing up for some reason
 
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No photos are working,harbeers aren't either just the embedded image
So how to you put it together?
Drill the hammer heas?
 
John mc c said:
No photos are working,harbeers aren't either just the embedded image
So how to you put it together?
Drill the hammer heas?
Click to expand...

I seem to have embedded the photo twice, but I can't delete it because it doesn't show up at all in the editor.

Anyway, it was pretty simple. I'm no machinist so if I can do it, anyone can.

https://www.harborfreight.com/16-oz-ball-pein-hammer-69010.html

1. I got a 16 oz ball pein hammer from HF for $5, and ground a flat face on the ball (is that what that part is called?)
2. As you can see by the burn mark on the handle, I tried to soften the steel with a torch before drilling. It skated a file before, and after the torch it seemed to let a file bite a little bit.
3. Much to my surprise, cheap titanium coated drill bits (3/16" pilot followed by 1/4") from HF dug right in without ruining the bits (maybe the hammer wasn't that hard to begin with?)
4. I had to do some work with the tap, just grinding length wise and a little bit on the sides so it could fit in the 1/4" hole
5. I used super glue to bed the tap in the hole

If you have to buy a tap or cheap carbide drill bit to use, then maybe it's a $15-20 project, but I had everything but the hammer so it was $5 for me :)
 
When you’re straightening blades with this method are you striking the inside of the curve? The idea being that you’re spreading the steel on the struck side to push it straight?
 
CallumRD1 said:
When you’re straightening blades with this method are you striking the inside of the curve? The idea being that you’re spreading the steel on the struck side to push it straight?
Click to expand...

Yes to the 1st question.

I believe that is the gist of it.
 
HSC /// said:
I also use the carbide peening method for my mono steel blanks and it works great. Japanese tagane. I use an impact grade carbide chisel with hammer
YHOYhrc.mp4
Click to expand...
Does it have to be carbide chisel? OR, would a HSS type work?
 
Ken H> said:
Does it have to be carbide chisel? OR, would a HSS type work?
Click to expand...
Yes. It has to be harder than the steel
The chisel I’m using is in the 70’s as I recall

I don’t think u can get steel that high of hardness
 
HSC /// said:
Yes. It has to be harder than the steel
The chisel I’m using is in the 70’s as I recall

I don’t think u can get steel that high of hardness
Click to expand...

I’m curious about your chisel. Where would a guy pickup one of those? Kind of fascinated there’s a carbide chisel that won’t chip-which is pretty cool.

Jeremy
 
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