Stupid Heat Treat Question

[Lenny]

Uh, please don't laugh at this question, but I just have to ask.
Is knife steel heat treated before or after grinding it into a blade?
If before, doesn't this wear out the maker's tools quicker?
What am I missing here?
Thanks,
Lenny

 

[MNH]

I would assume that everything is done except the final edge and blade finish before the heat treatment is done.


Mike

 

[Tom Anderson]

Actually, the amount of grinding that is done prior to heat treatment is pretty much up to the maker. Some makers grind very near final dimensions, some rough grind only, and some don't even grind the main bevels. All have their reasons, which are usually based upon experience with warpage during heat treatment.

However, most machining operations (drilling, milling, etc.) are best performed prior to heat treat. After heat treat, the blade steel is very difficult to cut without the use of carbide tools.

Makers who use specialized alloys that don't require heat treatment (such as Talonite) face a certain degree of difficulty in both grinding and machining when compared to working with blade steels that require heat treatment.

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Tom Anderson
Hand Crafted Knives

[This message has been edited by Tom Anderson (edited 02-19-2001).]

 

[Joe Talmadge]

Well, you learn something new every day. Tom, I'm surprised by what you say. mOSTmakers I've talked this over with grind the basic shape, then heat treat, so what's left is just the final finish (satin, mirror, bead blast, etc.) and putting on the final edge. Certainly, I've never heard of anyone not even grinding the main bevels until after heat treat! I'd guess that grinding the main bevels would both be extraordinarily difficult on a heat-treated blade, but would be enormously difficult to do without ruining the temper, so the knife would have to be treated over again.

Joe

 

[Don Cowles]

Joe- Post HT grinding of main bevels usually only happens on smaller blades like those used in folders.

 

[Rob Simonich]

Tom is right, doing quite a bit of heat treating for other makers as well as myself, I have seen a lot of small folder blades that arent ground at all on the bevels. Whe I make small thin blades I grind em hard as well. Just have to keep them cool!

 

[Tom Anderson]

Joe:

I think it really depends on a particular maker's experience with how the blades have come back from heat treating. If they come back warped, you're going to leave more stock on the next time!

Of course, if you're shooting for a fine ground finish, the abrasives will give you a much better polish on a hardened piece of steel. You just have to control the heat input to make sure you don't lose the temper. (This applies to sharpening the blade as well as cutting the main grinds.)

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Tom Anderson
Hand Crafted Knives

[This message has been edited by Tom Anderson (edited 02-19-2001).]

 

[Joe Talmadge]

Thanks for the explanation guys!

Joe

 

[Crayola]

And thank-you from me too! I have some 1/16" thick 440-C that I am going to make some kitchen knives out of (mparing/small utility knives) and maybe I should profile them and then send them out to heat treat, grinding the blades AFTER the heat treating is done!

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"Come What May..."

 

[Lenny]

Interesting stuff gentlemen.
I guess it isn't as cut and dried as I assumed.
One thing I don't understand though is why would a maker decide to heat treat prior to grinding the main bevels? This obviously complicates matters what with requiring carbide tools, and good cooling, and the chance of ruining the temper.
Thanks again,
Lenny

 

[Kit Carson]

I grind most blade steels after the heat treating cycle.

I do this for several reasons. On 420V (S90V) I have found it just performs better. With the higher temperatures used in the hardening phase, it is prone to warping, especially in the thickness I use on the F4 Neck knives.

Most heat treating manuals I have real say it is better to grind after heat treating.

With the newer belts (3M Regalloy and Cubitron) it grinds just about as easy. I grind with a variable speed grinder and do it barehanded, so loss of temper is not an issue.

I imagine I'm in the minority of makers that grind after heat treating.

 

[Arthur Washburn]

I grind my folder blades after I heat treat them. This prevents most warpage. The only thing I grind before heat treat are larger fixed blades.

Arthur D. Washburn
ADW Custom Knives
www.adwcustomknives.com