Working with K390. Tips needed!

[Huntsman Knife Co. LLC.]

Hey guys,

So Ive finally decided to try and make my first knife. Ive been lurking here for a very long time and have learned alot of great info from all the makers here.

I was ordering some epoxy and G10 form alpha the other day and saw a piece of .116 X12 X1.5 K390 for only $21!!!! I couldn't resist so I purchased it and it arrived today. I know K390 is probably not the best steel to make a first knife out of but for the price I figured why not

Im planning on making two knives with it each having ~4.5 inch blades and using the composite handle style that Phil Wilson uses in his knives.

My setup is the 42X2 Craftsman belt sander. HT will be done by Peters. With the technique I'm using I shouldn't have to do very much shaping of the sheet stock. I plan on doing either a flat grind or a very high saber grind with metal guards for accurate plunge lines and some dye or paint for grinding visibility. I'm thinking for belt progression ill start with 60 or 80 and finish with 220 or maybe a little higher and then send off for HT. Final finish will be done with nylon mesh wheels and edge will be finished on paper wheels.

What are some tips and tricks for working with K390? How thin should I take the grind? Also the knife will be a hunter/ bushcrafter. What hardness should I go for?

 

[OTK]

Well...K390 is indeed an awful choice for your first knife, but hey...hats off to you for trying this steel.

Working the steel pre HT is not much different than other steel. A bit harder to drill and grind but not a ton. The closer you can comfortably get the edge to final thickness before HT the better....you will have a hard time grinding this after its hardened. I'd go to about .025-.030" and leave yourself a little height to the spine. A 220g finish is fine. Finish grinding is best with ceramic belts and a lot of patience.

Good Luck!

 

[Huntsman Knife Co. LLC.]

Thanks for the input.

I made sure I got a pretty thin piece so I wouldn't have to remove a ton of steel.

It's going to be a challenge but I know I'll have fun with it. And on the bright side if I start using lower wear resistance steels like CPM 154 it should be a breeze to grind!

 

[Big Chris]

When I used K390 for the first time I only had a 2x42 to work it. Be sure to use ceramic belts. I do initial grinding with 40 grit, but the 60 or 80 (wont remove metal too fast) may work good till you get the hang of flat grinding.
When you are drilling use good quality drills and go slow. I had an issue with it wanting to work harden on me.
As far as HT I had mine hardened to 62 for a little more toughness, but it could go higher. Having it to do over I would HT a little harder, I have not been impressed with the edge holding at 62.
Good Luck
Chris

 

[Huntsman Knife Co. LLC.]

Thanks Chris! Looking forward to the Nessmuck you are making me:thumbup:

I think Im going to have this one HT'd to 64 or 65.

 

[Big Chris]

First day home with new baby and forgot to send the new sketches to you, we are very busy.

Back on track, That sounds like a good hardnes. I also forgot to say that I would aim for an edge thickness prior to HT in the .020" to .015" range. This is a good working thickness and you can go thinner after HT if you wish.

 

[OTK]

When I used K390 for the first time I only had a 2x42 to work it. Be sure to use ceramic belts. I do initial grinding with 40 grit, but the 60 or 80 (wont remove metal too fast) may work good till you get the hang of flat grinding.
When you are drilling use good quality drills and go slow. I had an issue with it wanting to work harden on me.
As far as HT I had mine hardened to 62 for a little more toughness, but it could go higher. Having it to do over I would HT a little harder, I have not been impressed with the edge holding at 62.
Good Luck
Chris

That sounds a little weird about the edge holding. I've always found it to be excellent. It will definitely be better up towards 63-64 though.

Agree on the work hardening. I you use a dull bit and heat it up a little, it can be a problem.