Hope I didn't steer him wrong...

K

Knifemaker.ca

Dealer - Purveyor
I had a guy call me today for advice. He is a trapper - and sharpens a couple thousand blades a year for other trappers. These guys are spacialists and use a silly fine edge - 3 degrees per side. They know that even touching a bone toasts the edge but they like it that fine.

Someone brought my friend a blade he said was titanium - and apparently, it took a very keen edge. He wanted to buy a bunch of titanium to make blades with. I told him I didn't think ti would hold an edge.

He only wants stainless - but wants a high performer. He ordered some CPM S35VN and I included some blade size samples of 154CM and CPM154. He asked they all be hardened before shipping. He's used to working with hard steel (planer blades etc) and knows to keep them cool enough to touch

Any feedback - particulary on the ti - is appreciated

Rob!
 
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You are correct in telling him that Titanium will not hold an edge, UNLESS proper steps are taken and the Titanium is modified. Most knife makers who make Ti knives "carbidize" the edge using a specially machine called a carbidizer which essentially uses electricitry through a carbide conductor to deposit little pieces of carbide all over the blade.

Now, I don't have any experience with carbidized edges, but from what I understand, it has certain "side affects".
While it does make a very durable edge coating that stays relatively sharp for "rough cutting" (i.e., rope, wood, cardboard, etc...), it's very hard to get a "fine" edge. And if you do, it's probably not going to last. It more/less makes the edge "toothy". So if you're looking for something to shave with, you'd better bring lots of toilet paper. ;) As far as skinning and processing game, I'm not sure how appropriate a carbidized edge will be, but I doubt they'll be getting the same results as a 6 degree edge with it.

That being said, I'm not sure how "specialized" these guys are, but if someone asked me to sharpen there skinning knife with a 3 degree angle per side, I'd think they were joking. Heck, I woudn't even put that kind of angle on a straight razor.
I'm not trying to sound like a jerk, or a know it all, but something tells me that if he understood edge geometry a little better, he wouldn't have to sharpen "a couple thousand" blades per year. If you catch my drift.
 
Yeah, 3 degrees per side is just crazy. I recently sharpened up a scandi style grind to 11 degrees, the edge is fragile but wickedly sharp. The primary bevels on most knives are over 3 degrees, and that's for a full-flat grind.
 
Yeah, he said he tried 2,3,4,and 5 and the guys preferred 3. I don't know how you'd even measure three and I haven't seen a sharpening guide that does it.

Anyhow, thanks for the responses on Titanium. It confirms what I've read in the past.
 
I concur with what's been said here about ti knives, I don't even bother with the stuff anymore.
A Super migraine headache was what I got from the bright white sparks it throws and I think it's some high Tec wizz bang bs as far as a functional knife is concerned.
It's works for liners on a folder darn well!

Not sure about the 3 degree bit? The lowest I go is a 11 degree edge on some specialized Fish/Veggie or Musical Instrument Reed knives.

I would ask for a reconfirm on the 3 Degrees, How is he arriving at that number?

Well That's my 2 Cents!

Laurence
www.rhinoknives.com
 
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rhinoknives said:
Not sure about the 3 degree bit? The lowest I go is a 11 degree edge on some specialized Fish/Veggie or Musical Instrument Reed knives.

I would ask for a reconfirm on the 3 Degrees, How is he arriving at that number?
Click to expand...

After thinking about it some more, I'm suspicious as well.

You know, I think a folded piece of tin foil will give you about a 6 degree inclusive edge.... ;)
 
I bet if the truth were known, it's a lot more than 3 degrees....I can't even think that small!
 
I'm with Andrew, for 3 degrees from each side you would have to start out with something about a thick a card stock and then taper it all the way back to the spine with no secondary angle. I don't think that surgical blades would have that angle.

Doug
 
You didn't steer him wrong. He'll quickly figure out that Ti will not make a good blade....at least for cutting purposes. The most you can hope to get out of any of the standard Ti alloys is a Rc48-50. As for the angle, I'm sure he's just making a guess at it....3 degrees would make for a paper thin blade (most razor blades are 15-17 degree angle...the disposable/replaceable types)
 
Doug Lester said:
I'm with Andrew, for 3 degrees from each side you would have to start out with something about a thick a card stock and then taper it all the way back to the spine with no secondary angle. I don't think that surgical blades would have that angle.

Doug
Click to expand...

Well, just using a little bit of geometry, you can figure that in order to get a 6 degree inclusive edge on a 1" wide piece of 1/8" stock, you'd have to full flat grind the steel to a zero edge. That's a LOT of material removal and a very paper thin edge.
 
I think Ed has nailed it that the edge bevel is a guess - realtive to other guesses. In any case, he isn't asking me to make him a knife, so I'm not going to argue the things he holds dear. His call was for blade material expertise and heat treat and I think we got that part OK - plus a couple to experiment with

So I know this other guy who wants to know whats the best steel to make a knife.... KIDDING!!!! :eek:

Thanks all
 
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