Straighten During The Temper

Stuart: Every advance we have made has been through our destructive testing and an obsession on our part to seek to make as close to our personal Excalibur as we can achieve. I fully understand your reluctance to destroy a blade, there have been times I felt that way about an exceptional cutter that we tested to the limit and beyond, but because of her sacrifice our next knife was better.
 
Here are the photos requested.
The pipe vise was bought at a yard sale for almost nothing. I normally have a pair of brace blocks under the lower plate, but left them out for the photos.
If you look at the side shot, you can see that placing the ricasso a bit above the clamp point will make the plates clamp in a taper to match the distal taper of the blade. Fourth shot is a blade after quench and clamping. It is dead straight.
 

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Thanks, Stacy. Are you waiting for the steel to hit the Ms range (15min or so)? Do you warm the plates prior to putting the blade in? There is still a lot happening until Mf... I would imagine cold plates would affect the rest of the transformation. Is it a compromise? (However imperceptible to the end user it may be... lol)

Rick
 
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Tai Goo said:
I think someone should give Rick an honorary degree in metallurgy... :)
Click to expand...

I did stay at a Holiday Inn Select....:thumbup:

I am like a mosquito to the bug-zapper. I see the light of metallurgy and just when I think I'm close enough to touch it, I get burned. Like the mosquito, it is in my nature to suck.


Rick:p
 
No hey! I'm serious Rick.

... You're a lot smarter than you look! LOL

I like the way when one guys argues one side of the equation, you argue the opposite. Where'd you learn that? I think it's working!

I also like the way you try not to overlook the obvious... I think most of us tend to make things harder and more complicated than the really are,... or need to be.
 
I think we should just stay the course we’re on and see what we can learn from it...

… but yeah! Everything we do to the steel by working it geometrically, thermally, mechanically, abrasively, (telepathically, spiritually) etc., changes the internal stress and/or the way it expresses itself… work hardening, re-crystallization etc.

Yadayadayada...
 
Rick and Tai,
I use the plates for cooling the blades during stress relief, and they do warm up to probably 150F or so.
In the final HT,the steel is quenched in oil, withdrawn after dropping below 1000F, and checked for straightness. After any quick twist/bends done with the HT gloves on, I set it on the plates and then clamp down the top plate.
While the plates do increase the rate of transformation, I don't think it is an issue with most steels.
On a water quenched 1095 blade, maybe I will heat the plates to 400F. Maybe that will give almost a martempering effect. I'll have to experiment with that and see what happens.
Edited to add in 2018 - I tried it, it wasn't worth the trouble.

Now you have my brain going to "plates version 2.0". What if I cut two slabs of insuboard, glued them to two pieces of 2X4, and used them for the clamps? Slower cooling rate through the Ms, no twist or warp, and closer conformation to the blade shape........Back to the shop tonight.
 
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This is some great stuff guys, did my first longer blade today and got just a little warp in it. Now I know what I need to get ahold of to try and fix it up.
 
Thankyou very much for this information... I'm in the process of making my first knife, and have got a warp after the quench process.. will clamp it and see how it goes after the tempering stage in the oven at home...
Cheers..
 
Just adding my 2 cents, actually 1 cent. I just used a penny to shim out a wiggle I had in a blade. Angle iron that has been flattened as smooth as I can get it, 3 claps, a penny and an hour in the oven. Didn't need it in the second cycle.
 
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