Recommendation? Puukko Question take 2

What would you do?

  • Learn to sharpen 63 HRC

    Votes: 0 0.0%

  • New blade in old handle

    Votes: 0 0.0%
  • Total voters
    0
T

tom57

Joined
Dec 28, 2009
Messages
11
Hello again.

Thank you all again for the help previously but I knew my project was going too well!

The blade in my puukko is a Laurin PT 80mm carving blade which is progressively heat treated. The edge hardness of this blade is supposedly 63 Rockwell and I cannot for the life of me sharpen it without the edge chipping out. My burr chips off leaving a ragged edge every time.

Now as I was after something I could get some proper use out of Im not sure I want to deal with such a finicky blade.

So my question is how likely is it that I can remove the handle without damaging it to repurpose it for a new blade? It is a through tang construction, peened at the end on a pommel. My thoughts would be to file off the peen and set up the knife so i could give the back of the tang a good knock with a hammer to break it loose.

Let me know what you think!
Cheers,
Tom
 
Yes I did use epoxy.

Ive actually just managed to get the handle off very successfully by putting it in a zip lock bag in boiling water. The only parts I need to replace are the leather spacers.

Is it necessary to remove all the old epoxy now its been softened by the heat from the hot water before I glue the parts onto an new knife tang?

Cheers.
 
Yes remove the old epoxy.
You want the handle to be attached to steel, not to old glue.

You can sharpen steel like that with duamind plates. You can get then cheap from China or quality stuff ftom DMT or Ezelap
 
I
Hengelo_77 said:
Yes remove the old epoxy.
You want the handle to be attached to steel, not to old glue.

You can sharpen steel like that with duamind plates. You can get then cheap from China or quality stuff ftom DMT or Ezelap
Click to expand...

I may have misunderstood you but I mean remove the old epoxy from the inside of the handle material. The new blade I have on the way is from the same manufacturer so i'm expecting a similarly sized tang which I think the old handle material should fit quite nicely without too much work.

Heres a photo of what i'm left with.

pZEScVY.jpg
 
Epoxy hardens, it forms bonds between molecules. It is a chemical process that you can't reverse. You've destroyed the bonds between the molecules, what is left are loose molecules.
New epoxy will adhere to loose molecules, not form new bonds between the old ones.

See it like loose gravel, you can glue to the top layer but it won't stick to the layer underneath
 
Yeah that makes total sense. I'm wondering if it'll be an issue if the epoxy in the handle material is just to prevent rotation on the tang as the through tang will be peened over the end of the handle material.

I'm just thinking out loud here in relation to the alignment of the now shaped pieces on the tang as i'll be reintroducing some slop by drilling out the old epoxy.
 
63RC is not outrageously hard and it sounds like it’s just a simpler carbon steel with a torch drawn spine reading through the description of it. What kind of stones are you using? I use naniwa chosera water stones so not even diamond and 65RC 26C3(carbon steel) will sharpen fine on them.
 
imill3567 said:
63RC is not outrageously hard and it sounds like it’s just a simpler carbon steel with a torch drawn spine reading through the description of it. What kind of stones are you using? I use naniwa chosera water stones so not even diamond and 65RC 26C3(carbon steel) will sharpen fine on them.
Click to expand...

I was using a spyderco sharpmaker which usually I have no problems with. Form a burr, flip etc. But I couldn't really get a consistent burr with the blade and what there was would just break off leaving chips on the edge. I could see tiny slivers of steel breaking off as I sharpened.

I do still have the blade undamaged, Its just not in the handle anymore :rolleyes:. The blade I have coming is https://www.brisa.fi/supplies/knife-blades/woodsknifes/wk-carbon-90.
 
Sorry to hear that this build went sideways on you at the last minute..

You could try tempering the old blade to see what happens. Just stick it in the oven at 400F for a couple of hours.
 
Yeah it's not ideal just more money sunk into the project... I was gutted but seeing as the handle is still in one piece i'm happy so the re-handling should be ok.

That is something I may try for a future project but for the time being and I may keep having a go at sharpening the old one but I have another blade on its way to me.
 
The Lauri PT blades are induction hardened. The edge is passed between coils. One of my best friends was the UK importer for Kellam Knives for a number of years. Their Wolverine model used such a blade and was very popular in the bushcraft crowd. I used to have a blade that I put my own handle on, but sold it in a moment of short sightedness! They can be terrifyingly sharp, and can most certainly stand up to use. The bushcraft instructors I know who used the Wolverine as their primary knife didn't shy from using them to split and cut with the aid of a baton.

Tom.
The problem is probably not the blade, but that V-stick sharpeners are not very compatible with very hard, very thin, edges. I have a Sharpmaker. I bought my dad one, which he is able to use, but we did have problems when we first tried it on his Murray Carter santoku with hard Blue Paper steel core and fine edge. In V-stick configuration I was not able to avoid popping lots of little micro chips from the edge. Same thing happened with a radiused diamond kitchen rod type sharpener.

What is needed is to increase the contact area of stone to blade. This is very difficult, even on the flat sides of the Spyderco triangle stones, when they are V-stick mounted. Its a little easier with them laid flat and parallel on the back of the box, but the best way is to hand hold them like files. This however isn't a particularly safe way to sharpen! It does not help that the "flat" sides of the Spyderco rods are not actually flat either, so at best you are contacting in narrow bands, should be enough, but it wouldn't be my first choice.

There are lots of options for sharpeners that will work better with that blade. I would put another handle on it and give it another try. Rather than spend $$$ on a water stone, if you don't have one, I would use wet and dry sand paper, 600 - 1200 grit, stuck to a flat backing and "strop" the knife, wiping the full bevel against the paper, away from the edge so you don't cut the paper. Then strop on card, balsawood or thin leather on a hard backing, loaded with the compound of your choice, I like the solvent based chrome polish type that comes in tubes (abrasive tooth paste) rather than the solid bars.

In any case, the wide bevel of puukkos works better on larger flat stones where you get good tactile feedback of the whole bevel on the stone.

Best of luck :)
Chris
 
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A quick addition. The Sharpmaker is designed to sharpen at 45degrees for the average user's general cutting needs. Sal told me they expected more experienced users would use the 30degree setting for better performance, and maybe cant the blade to reduce the angle a little more.
Many puukkos are sharpened at 20-22degrees. When my Kellam selling friend and I were talking to Spyderco about the design of their Bushcraft model, the low angle edge caused quite a lot of consternation.
 
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