Custom Blade for BK2 handles... Built a tank.

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KOLONEL SOPDROL

Joined
Apr 6, 2013
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58
A while back I made some custom wooden grips and a leather sheath for my BK2.

This resulted in a pair of BK2 handles lying around. I reckoned the best way not to lose them would be to put them on a custom knife.

I merged a whole bunch of elements that I personally like into the design for this blade:

* 8mm 5160 spring steel.
* BK2 handle and pommel.
* Busse TGLB blade shape, size and finger choil.
* BK16 flat grind.
* Modified reverse thumb ramp of the BK7.
* Convex grind.

Work in progress pics - bad cell phone quality since my hands were damn dirty most of the time:


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Blade back from water jet cutting. I am very impressed with their accuracy. Cutting the blade cost $36. The steel was $10 for a 1m bar of 8x70mm


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Desired edge thickness marked before filing.


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Jimping detail. Here especially you can see how well the water jet handled the cutout.


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Custom made filing jig. This worked very well. I think the photo shows exactly how the thing works.


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Blade clamped and busy filing. I gave up at this point and had the blade belt sanded. I should have used a rougher file but for some reason none of the local hardware guys had any.

Before we started with the grinding, the blade was heat treated (or normalised) first to prevent issues while it was being ground. Apparently the heat up / cool down during belt grinding causes problems with 5160.


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Finished belt sanding. Since I was not sure about the accuracy of the water jet, I left a little margin around the handles just in case. This was totally unnecessary and caused me a bit of extra work later on.

The blade was also hardened to about 58 on the rockwell scale. A local knife maker did the heat treat and belt sanding for me. He really did an excellent job on the belt sanding and ht!


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Cutting edge. To prevent warping we left about a 2 - 2.5 mm cutting edge. Not sure if this was really necessary on a blade this thick, but decided to play it safe.


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After sanding the blade to 100 grit. I used the same filing jig for the sanding to get everything as flat as possible.


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Finished sanding.

Because of the thick edge, a convex grind was my only option for this blade. I also thought that the durability of a convex edge would suit the character of this blade well.

Convexed the blade by filing about a 30 degree bevel as far as I could, then belt sanded on a small tabletop belt sander. Stopped screwing around with this when I cut myself with the tip ; )

Stuck the blade in a couple of lemons to see what the patina will look like.


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Still to do:

I think the convex edge can be taken up a bit higher for better cutting. Some cutting / chopping / slicing experimenting will be required. Talking of experimenting - this morning I tried whacking the blade at a nail - the wood I put the nail on gave way so the nail was only cut through about halfway. No damage to the edge whatsoever.

Finishing - I am a bit undecided on this. I intend to use this blade and use it hard. Dont think I am going to bother sanding to higher than 200 grit.

Sheath - probably kydex.

It weighs just over 600g with the handle. The balance point is within a couple of millimeters of the two holes in the guard.

Take some SLR photos....
 
Great project, very interesting. I especially am intrigued by that reverse thumb ramp and how it would feel. Great knife by the looks of it. Very unique. How does it feel in hand?
 
Its quite comfortable. The angle on the ramp lines up perfectly when I put mu thumb on the spine - both when holding the knife normally and when using a choked up grip.
 
Very cool. Where did you get your design waterjetted if you don't mind my asking?
 
Very interesting design. I look forward to hearing your impressions after you take it out into the bush for a while!
 
That knife looks like a beast! I might have missed it but what are the dimensions of it? It looks over 0.25" thick...

Pretty awesome work.
 
DerekH said:
Very cool. Where did you get your design waterjetted if you don't mind my asking?
Click to expand...

Hi Derek,

A company in Nelspruit did the water jet cutting for me. I am not sure what make of machine they used - but it has a 4 x 2m bed. The kerf width is about 0.5mm.

Its quite remarkable that such a big machine can handle fine detail this well....
 
orezona said:
That knife looks like a beast! I might have missed it but what are the dimensions of it? It looks over 0.25" thick...

Pretty awesome work.
Click to expand...

Hi Orezona,

The overall length is 335mm.

The blade is 40mm wide and 8mm thick - 5/16

The blade has a very slight taper - from 8mm at the handle to about 5.5mm an inch from the tip.
 
Some feedback after playing around with it last night:

I really like the convex edge. Sharpening it is very quick. One or two backwards passes over sandpaper on a piece of HD foam is all it takes to get the edge back.

The BK2 cuts better due to its thinner edge. I tried cutting some carrots - The bk2 goes in deeper before the carrot splits. With the custom the carrot splits a lot sooner.

I cut the carrots on a normal plate. From hitting the plate, the BK2 edge is damaged more than the custom. (Edge geometry rather than 1095 vs 5160 I think...)

Retouching the convex edge on the custom is a LOT quicker than setting up the Lansky for the BK2.

I never paid any attention to the guys convexing their knives, but after dealing with a convex edge, I think I might put one on all my Beckers...
 
KOLONEL SOPDROL said:
Some feedback after playing around with it last night:

I really like the convex edge. Sharpening it is very quick. One or two backwards passes over sandpaper on a piece of HD foam is all it takes to get the edge back.

Retouching the convex edge on the custom is a LOT quicker than setting up the Lansky for the BK2.

I never paid any attention to the guys convexing their knives, but after dealing with a convex edge, I think I might put one on all my Beckers...
Click to expand...

That's how I sharpen all of my knives actually. It works great :). In fact, I do the same for my non-convex edges (just don't use the mousepad that I use as my "foam"). I find that sandpaper is my favorite way to sharpen, as its easy, cost effective, and gives a great edge :).

Oh, and nice work on the blade, it looks great.

But man, I can't imagine how heavy it must be at 5/16. Must be great at battoning :).
 
I think that usually there's a second grinding (on the same primary bevel) after heat treat that brings the edge thickness down before sharpening.

Awesome looking knife, looks like a beast.

Sweet file rig, also.
 
What a nice way to get rid of handle waste ....... Nice job...... Like the design in a lot of ways....... I repeat....Nice job!!!!!!.... What's next??......

Ethan
 
Dude. Duuuude. That is awesome! Love it! Like TBL said, can't wait to hear of your impressions after a bush outing. That thing looks like it'd cut down mountains. And to have the Boss impressed? Well. That's really saying something bud. Onya Kolonel!

Oh yeah, as for the "reverse" thumb ramp, I find that I use the forward side of the ramp on my 7 when I choke up on it. Actually seems to work better. IMHO.
 
Hi Ethan,

Glad you like it!

I really like the handles on the BK line of knives, and that was the inspiration behind this knife....

Some more pics:

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Overall view taken with a better camera.

I took the convex edge up a bit higher and flattened the transition between the convex edge and the rest of the blade a bit.

It would have been easier with a proper knife making belt sander instead of one of those cheap tabletop sanders, but it will work.

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Comparison to one of my BK2s. This is the BK2 I made the new handles and leather sheath for.

Both sit about the same in my hands. The custom has a thicker tang, but the wooden handles on the BK2 are thicker...

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Spine shot.

You can see a marked difference between the tangs.

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Zoomed out a bit.

The custom has a very slight taper ground, going from a thick tang to a slightly slimmer blade.

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Blade geometry comparison.

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Another view. I am not really keen on shiny knives to I treated the blade with mustard and vinegar to get a patina going.

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Blade comparison, BK2 left, custom right.

Use report:

I havent had a chance to use it out in the field yet. Before doing that I will have to make a Sheath first.

I am considering leather again.

Chopped a few nails in two - no notable edge damage... Used a hammer and the knife to break open a few macadamia nuts.

Despite its weight its not really blade-heavy enough to be classified as a chopper. Feel-wise it is closer to a very heavy bowie.

Talking about weight: It weighs in a 610 grams compared to 460 grams for my BK2 with the wooden handles.


Whenever we go to our local pub for a rump steak, I always take my BK2. Those little steak knives are a joke in my opinion...

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I will be testing the new BK on a steak sometime this week....
 
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Very cool comparison, and definitely puts into perspective how big of a beast that thing is!
 
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