Building a Karambit Putting a edge on a concave blade, not so easy. Knife is finished

kenhills

kenhills

Joined
Dec 17, 2007
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Hi All,

So this will probably take 2 or 3 days. !st day make the blade take it from concept to finished blade. Day 2 heat treat and re-polish. Day 3 handle and and polish everything to a luster. The first 6 pictures represent about 4 hours of work. I had to go slow creating the edge on the concave cutting surface of the blade. It cant be done in the traditional manner. Instead of moving left and right on the KMG machine the blade has to be held vertical and moved up and down against a 10 inch wheel. Top edge was no picnic either ... concave grinds on convex edges. You knife makers know what I am talking about. Comments are always appreciated so chime in.

Concept drawings and a hunk of Aldo's 3/16ths 154-CM 2 inches wide.


Drawings transferred to steel then drill the holes for the pins and the slot (blood groove) milled out.



Cut out on the Band Saw then roughed out with a 60 grit belt on the KMG machine.



Finished blade shape and the initial edges are ground into the metal.



Edge taken up to 1200 grit the rest of the knife is left at 450 grit for contrast.



Close up of the finished edge. Now I remember why I don't do a lot of concave edges.



Tomorrow heat treat and if time allows a final polish. I think I am going to go with black canvas Micarta scales. More tomorrow.
 
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No it is not a chisel edge. Typically I do a hollow grind but on a concave edge like this one that is not possible. Not with the equipment I have at any rate. One of these days I am going to get the folks at KMG to make me a special wheel so I can hollow grind knives like this one. The design is in my head and it will work just have to put it to paper. For lack of a better term I would call this a shallow convex grind. Same sort of grind you would find on a Kris, which was the other one I was considering. I have done a few of those and they are a f*&%ing nightmare to keep true. I don't know if you are a knife maker but any time you get into a concave blade design it becomes very difficult to keep the bevel and edges true. It is a very different way of grinding, it is not at all intuitive, for me at any rate. Hope that helps. Ken
 
As promised some more pictures of the Karambit in progress and a surprise.

First few pictures are more shop pics than of the knife specifically.

The Paragon Furnace in the final hardening cycle at 1950 degrees Fahrenheit. Thats white hot and just a little scary got to be careful when taking it out.



All set up ahead of time white hot is HOT. that's the paragon KMG machine on the left. The aluminum plates will be used to rapidly cool down the 154-CM blade.



The envelope with the blade is sandwiched between the aluminum plates and I will be blowing compressed air through it to cool it even faster. Thats about 7 lbs of weight on it.



After about 5 min. this is what the envelope looks like "hot potato". Now into a toaster oven at 300 till my furnace cools down to 450.



The knife after hardening and tempering.



Surprise there is a unusual very hard oxide on the steel not sure where it came from but I like it so I am going to keep it and only polish the cutting edge and the false upper.



It has a very nice contrast and given how hard it was to polish it off (actually had to take it back down to 220 to remove it) the edges I don't think it is going to scratch. Here are a few closeups. Never seen this happen befor and I use this steel all the time. Any one got any ideas?





It is hard to see in the images but the flats are a medium grey from the oxide and the edges are polished to a mirror silver.

Comments?
 
The Karambit all glued up the pins will be peened into the slight conical hollows that I bored into the outside of the scales when the Gorilla glue is dry. That's a through back to my jewelry making days many years ago.



Now cut off the excess pin material leaving about 1/8 of an inch extending on both scales and peen in place.



Once the scales are peened in place sand flat.



Next step shaping the scales. Comments?
 
The finished Karambit or if you prefer Hawkbill knife.

Overall 9.75 inches made from 3/16ths 154-CM hardened to a Rockwell 60-61. Mirror finish on the spine and edge as well as the surfaces that show on the tang. The flats of the knife have a matte grey oxide finish that is VERY hard. Blade is 5 inches from the scales to the tip. Cutting edge is 4 inches. Scales are made from Black Canvas Mikarta taken to a very high polish. Pins are made from 416 and peened in. Comments please. Thanks for looking hope you enjoyed the project.



















I will be heading off the the Gun and Knife show with it this weekend. Thanks for looking, Ken
 
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On most of my knives, you can see them here, or on FB under Mongrelknives, have a lot of file work on them. I was looking for a price point here which translates in to hours spent on the fabrication of the knife. This is about 8 to 9 hours of work. If I work the jimping in to it in the fashion I am used to doing, Vine and thorns pattern, between the filing and the polishing I would be putting in another 2 hours or so. As it is, the curved spine of the knife and the shape of the scales are going to keep your hand where you want it. If I was not comfortable with the "feel" of the finished piece then I would have gone back and worked some sort of pattern into the spine. Remember in a blade shape like this the cutting is done on a pull not a push. Your hand when cutting is pulled towards the back of the knife not sliding forward. If you are talking about aesthetics then you are absolutely correct. I own it only if I put more embellishment in to it. Ken
 
Looks good, you can certainly hollow grind these. You can carefully use the outer 1/3" or so of your contact wheel. But, a 1" wide wheel is truly the way to fly for curved blades!
 
I was thinking of having KMG make me up an 8" wheel with a convex surface 2 inches tapering to a 1 inch convex surface. Thanks for the tip I will give it a try.
 
I was jokeing about the jimping thing, I had just watched a Nutnfancy video. But ya, the knife looks great. About what would be your price on a knife like that?
 
Round numbers $160.00 plus the shipping another $25.00 for a Custom Kydex belt sheath. Ken
 
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