Heat treat question

A

amamachinist

Joined
Jul 6, 2012
Messages
136
Hi guys

This is my first post here I'll try not to F it up.

I am in the process of making my first knife. It will be a fixed blade about 6" long contoured on a mill.
I am using a piece of 5/32x1-1/4 O1 flat stock.
I am wondering when I should do the heat treat? Before contouring after contouring but before rough grinding or after everything??

Also I wasn't planning on heat treating it myself but having a pro do it for me. Is it easier than I think? should I do it with my torch?

thanks for your help
Nick
 
I would grind to at least 120 grit before HT. Leave the edge thick enough for more
grinding post HT, say .040". Don't try to HT O1 yourself with a torch.
 
0.040" is hugely thick, IMO.
If you're going for a pro heat-treat of O1 you won't have much decarb layer, and can probably go a good bit thinner.
Grinding hardened steel sucks.

But yes, get to at least 120g, preferably more. Especially if you plan to hand-finish it, Get up to ~400 (for the same reason as above).

-Daizee
 
The short answer to your question is that all work , except final sanding and sharpening, must be done to the blade before HT.



Since you are milling the blade, we will assume that all the flats will be good and flat. Hand or machine sanding to 120 grit before HT is needed. Taking it to 400 is a good practice, especially if getting it professionally HTed.

The edge should be thick enough to avoid warp and ripple in HT. For a machined blade in O-1 that will be professionally heat treated, I think you will be fine with a .020 edge thickness.

Be sure to give the heat treater all the info on the blade, including that it was milled to shape and has other machine work done. They will want to do a good stress relief before the austenitization.


Welcome to Shop Talk.
Filling out your profile is always a good thing to do.
 
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