How Much Pre-Work Before Heat Treating?

Hello Everyone,

I've done some searching and reading in these forum and also the tutorials but really didn't get a definitive answer:

When working a blade, how much grinding, sanding, etc must be done before heat treating?

I've found out that it should be profiled, holes drilled, blade ground, etc but ground to a sharp edge or save that for after the heat treatment? I'm curious as to how much "should" be done before and afterwards.

Over the weekend, my buddy and I worked out a design and I've placed my first order for some 0-1 and will be creating my first blade soon

Thanks for your help and sharing your expertise with me!

Best Regards,
Pete

It would be great if we could take the blade to a finished state prior to heat treat and have it come out the same way. We cannot, so we need a good balance point. Things to consider are warpage, heat coloring and/or scale, and microfractures.
When working with your typical steel, I personally recommend something in the 220 to 400 grit range because finish work is not terribly difficult. If, on the other hand, you are working with something along the lines of S90V with a high vanadium content, I recommend taking it to a nearly finished state and hoping for the best in relation to warping. Those scratches are sure hard to remove after HT.

Brett

_ _ _ _ There is also the question of scale removal... if you are etching a damascus you will particularly notice that you need to remove about 1/32" or so to get past a 'marble,' looking surface resulting from oxidation during normalizing/ heat-treating. This can appear non-existent until the pattern etching after all your hard won finishing work.

_ _ _ _ You -can- grind a blade to finish and heat-treat it with no surface effects in heat-treating salts... but these things are quite the investment...

_ _ _ _ In the mean-time, you aren't the only one grumbling, grinding and finishing away after heat-treating... I allow myself an extra ten-percent material before heat-treating my simple 10xx series damascus. That way I also have room to grind away any warpage or visible flaws.

Speaking of heat treating. J, did you ever finish the salt pots?
I have my tubes done, but haven't completed the forge yet.
Mike

All I really have to do is re-order the right temp-controller.

Who'd a thought? 3-32 VDC doesn't mean it will operate a 12v device... So now I need the pricier Omron unit to operate my 12v solenoids. All the hard work is done though. I need to make the high temp salts and order the low temp salts...

Then all I have to do is fire 'em up and hope the burners are hot enough on the high temp and low enough on the low temp!

Just been too busy paying the bills to get to it...

I understand, please post some pics when you get them running.
Mike

If I understand the question, you're asking how much metal to leave before hardening and tempering the blade. From what I've read (and subsequently done) I leave about 1/16 of an inch on my blades, which I then grind off after quenching and tempering. This is supposed to (and seems to) get rid of decarburized material, leaving me with good hard metal. I'm using O-1, too (it's great) and I haven't had a problem with it warping at all, even in thin cross sections (like knives). I hope I didn't misunderstand your question, and hope this helps. I usually grind my blades to a 220 grit finish before hardening.

I'm going to second, third? that comment about 220 grit.

The only blades I've had crack lately were at about 100. There is some controversy concerning the direction of the sanding marks too... I have had better luck with them perpendicular to the blade, but others insist on sanding parallel to the blade. My reason for perp. lines is that the cracks almost always run parallel to the blade and therefore giving the cracks a long, parallel line to work with just seems counter-intuitive.

A thicker blade is less likely to warp as well. And especially with damascus, I'd rather grind down to a perfect surface unaffected by decarb than forge to shape and have a few blobs I can't remove because the knife is already the perfect shape...

Hey Everyone,

Thanks for the information on how much blade material to leave before HT. This is what I was looking for.

Have a good week!

Best Regards,
Pete

Almost forgot- round any sharp corners too!

Good Luck...