edge thickness before heat-treat

Joined
Jul 3, 2002
Messages
645
Rhino, you answered this question of mine in another thread, but I needed a bit of clarification so I made a new topic.

I was looking for a thickness for some kitchen knives. You mentioned .112 (someone else mentioned 1/8 as a little too thick, but workable) OK I ordered .112 for carving and .090 for paring.

However on the question of how thick to leave the edge (on another thread) you mentioned 1/32 to 1/16 (.031 and .06). Wow on those thin blades that's barely a grind!

I'm ok with that I just need to double check. I don't want to go to all the work of buying, shaping, heat treating only to have ruined the whole process!

So, on those thin guys I just need to shape, start the grind and send it in. Maybe not grind at all?

Steve
 
steve those numbers are a guess. i really do it all by eye. i dont scribe a center line or any thing. its just the way i do it :) the thin steel you are ordering is easier to grind with out bending the steel after HT. the edge it self is the very last thing before i put my logo on.
 
You mean not only do I have to wait for my steel, now I have to wait even longer before I grind it away!?:p Good thing I didn't use up all my scape yet.


OK I'll shape it; file in the beginning of the plunge cut; start the basic angle, then send it to Paul.

I really hope this stuff doesn't warp from the heat treating! I don't have much extra metal or time.

Steve
 
I'd like to throw in my .02. The amount left before heat treat also depends on the type of grinder you have. If you can't slow your grinder down some I'd get it down pretty close before heat treating. The reason is a fast grinder will burn the blade much easier than a slower one. Getting it close before HT means that you will have less to do and at least in theory, less risk of burning the blade.
 
What Peter said. How hot you can get the steel after heat
treat, of course, depends on the tempering temp of the heat
treat. ATS34, for example, the way Paul Bos does it, is about
900 F I think. D2, a steel that I really like, is much lower.
If the edge of D2 turns brown, while grinding after heat treat
, it's ruined! I notice that the tempering temp of CPM S30V is
about 600 F. With a fast dull belt, you could reach 600 F on the
tip of the blade in a heart beat. Of course 600 is a lot higher
than the simple carbon steels. ( 375 - 425 )
 
My worry was if it is too thin I risk warping (it's s30v). But maybe that's not the biggest worry.

Thanks guys.

But, I'm still a little confused.

Do I have to worry about warping?

Steve
 
Do I have to worry about warping?
Yes Steve, you do have to worry about warping....and cracking and burning and getting the right bevel and a hundred other things. In short you have to worry about everything and try to balance pre heat thickness Vs the chance of warping Vs the speed of your grinder, etc, etc. Welcome to the world of worry!:D

The NASA people used to sign everything "SDTAGW" in the early days. One of them fessed up at some point and told what it stood for.

Some Damn Thing Always Goes Wrong!

Don't sweat the small stuff. You will get your procedures down soon enough.:rolleyes:
 
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