I already have the knife almost all the way done (pic below, first time be gentle) but wondering when I get this thing put in a furnace to temper it should I sharpen it completely before going in or after coming out of the furnace?  Also how do you guys think AMS 5510 stainless steel type 321 work for this knife?  Little info on the steel. Thanks guys.  



Plan is to Cerakote it and do a para cord wrap for the handle or maybe Micarta.

Ok, so a few things about terminology

-Anneal: heat and slowly cool to create a soft, workable material
-Quench:  heat and rapidly cool to create a very hard, brittle material
-Temper:  Heat at a very low temp to slightly increase ductility while maintaining good hardness

I assume it's already annealed because you're able to work it pretty easily.  Go ahead and get the full shape, profile, and bevel that you want before the heat treat.  You can get it sharpish, but know that the heat treat will inevitably ruin a razor edge.  Another consideration is your heat source.  If you're using coal/charcoal and are relatively new at this, it may be tough to get uniform heat on the blade.  The thinner spots like the edge may heat up faster than the rest of the blade and melt/burn if you aren't carful.  Keeping the blade dull will prevent this to an extent.

You may already know this, but after this you'll heat the blade to non-magnetic and quench.  Then you immediately temper it in an oven before doing the final grinding/sanding/sharpening (be careful to keep the blade cool or you'll mess with the heat treat.


I actually don't have any experience with stainless, maybe someone else can chime in.

RED- I actually cut the profile with a laser.
BLUE- The furnace I'm using is a professional grade one that is used at my place of employment, don't make knives for a living.  The furnace is about the size of 4 pickup trucks.  

I'll make the blade edge about 75% finished and thank you for the terminology and input.

Free advice, worth what you paid for it >>> If you plan to put any more holes in the handle area, you might want to do that before you harden the steel to its final hardness.  If you are using a laser to cut the holes, this might not be so important...  just a thought...

It was free,  I think I might put two more holes in it because I think I'm leaning towards a Micarta grip.

is this a post from prison and you are gonna make several shivs and sell them?? just need to get the kiestering down

And what's the point of your post?  I asking about whether or not putting a final edge on before or after hardening is the better option.  But feel free to not post anymore in here.

You can grind the main bevel before or after heat treat.  If you grind after you have to keep it cool.  But the actual edge needs to be put on after heat treat.

Thank you.

Leave the edge a little less than the thickness of a dime. That will prevent edge warping during the quench and it will also leave you some metal for post heat treat clean up.

During post heat treat clean up do everything with your bare hands and when it starts getting warm dunk it in water. If the color changes the temper is ruined.

I'm sorry to be the bearer of bad news, but 321 stainless is not heat-treat hardenable.

I read that earlier today, kinda sucks but it's still a knife I can use for the most part.  I won't expect it to be perfect but I did look on amazon and saw a lot of steel blanks.  Now to figure out what type of steel to get that will be strong and hold a great edge.

If that happens can it be re-done or is it a complete loss?  When you say color do you mean the steel? Water?  Is it very noticeable?

The steel will change color.  Gold will appear first, then blue/purple.  That color is a higher temp than the temper.  I grind all my blades in the hardened state, but sharpening is the very last thing I do on a blade.  Look for a steel with a higher carbon content.  The one you picked has almost none in it...  1095 is a good first choice, or even O1.  I use CPM 154 or N690 stainless.

The steel will change colors as it heats up. It starts around 300-400 degrees and if it changes colors you really need to repeat the heat treat process again. The steel will lose its temper and the edge will roll very easily because it has lost its hardness.

If I was you I would order a piece of 1084 from New Jersey Steel Baron. It's a good simple high Carbon and can be heat treated with low tech methods.

Army11b has a thing for keistering. Ignore him. Keep working.

Was curious about his post.  I'm working on an updated design now and going to get better steel to work with.  Just have to work with the guy that's going to temper it to make sure he does it the right way.  I'll post some pics when I get the final design done with the correct steel.

I'd recommend sending the blade out for heat treating to a place like Peter's Heat Treating or Trugrit. Peter's will include cryo and up to 30 minutes of straightening. Trugrit takes smaller batches but cryo is additional cost.

Either place will hit the hardness you want +/- 1.  When you're just talking someone into heating and cooling a knife for you it's highly likely that neither of you really know what you're doing. A good consistent heat treat helps immensely when trying to figure out good edge geometry. If your heat treat has a lot of variance it makes testing different edge geometries harder.

I send my blades in batches of ~25 to Peter's. I make knives as a hobby and give away most of them as gifts. I like AEB-L and can't heat treat blades at home for the price I pay Peter's once I factor in a kiln, quench plates, liquid nitrogen, and time being the big factor. If you want to make a hamon or pattern weld then you'll need the gear but right now just take it in baby steps. Work on edge thickness, even plunges, equal grinds, and general quality aesthetic before getting fancy.

Good advice, thank you.