Latest knife build


Misc. Projects / Friday, January 9th, 2015

It’s been a long time since I posted anything, but it’s not from a lack of projects to report on, and I wanted to share the latest for any who might come across it. In particular, to share a few things I learned from working with some new materials. This is a classic drop point hunting knife with a handle made from Padauk wood and water buffalo horn, a nickel-silver bolster and cryogenically heat treated blade made from 440C steel.

The completed knife
The completed knife

This is the first time I used anything other than wood to fashion handle scales, and the buffalo horn was an interesting material to work with. It cuts and sands much like wood, and polishes to a nice finish. It’s also said to be very durable, so it will be interesting to see how it will perform over time.

One potential concern is that it’s a very smooth surface once finished, so time will tell if this translates in to it being slippery and difficult to hold on to in the field. Another thing I will point out about the material is that it has a very distinct odor when you are working with it, and the dust is fairly potent. The smell also tends to linger, so I recommend sanding and shaping it in a very well ventilated area.

One last thing about the buffalo horn, is that you must be very careful when installing the pins. When I initially installed the pins, the fit was a bit too tight and forcing the pins through caused the horn to get damaged around the holes. It’s hard to explain what it looked like, but essentially the force caused the layers of the horn to separate, and want to chip off. Ultimately I ended up enlarging the holes to remove the damaged portion and using rivets rather than peened pins to prevent it from happening again. Though the material isn’t hard, the holes themselves were also challenging to drill without chipping the edges. I ultimately had better luck moving slowly with a hand drill, rather than a power drill.

blade.jpg
The blade and bolster prior to starting the project.

I purchased the blade and bolster, but both required shaping. I didn’t like the sharp angles on the tang, so I used a belt grinder to slightly reshape it. The bolster was essentially square stock and had to be shaped using a combination of files, a Dremel and the belt grinder.

I used a permanent marker to color in the material to be removed to help keep it symmetrical and guide the shaping process. The main thing when shaping the metal is to go slow and check your progress frequently.

The shaped bolster.
The shaped bolster.
The bolster during the shaping process.
The bolster during the shaping process.

 

 

 

 

 

 

 

 

At this point I also finished and polished the front of the bolster, since this is much more difficult to do once attached to the blade. It’s nearly impossible to get a good finish without scratching the blade once in place. To help protect the blade, and my fingers, I covered it with masking tape for the duration of the project. Once the bolster was shaped, it’s attached to the blade using a pin, which I peened with a small hammer and anvil to secure it. Once this is done, I used a grinder to flatten the remaining metal.

The pin after peening.
The pin after peening.
The bolster after it's attached and smoothed.
The bolster after it’s attached and smoothed.

 

 

 

 

 

 

 

 

 

The buffalo horn scale.
The buffalo horn scale.

I then begin work on the handle. The first step was to flatten one side of each of the horn pieces, to ensure a solid fit. I did this by lapping it flat on sandpaper attached to a piece of marble tile. You can see in the picture very clearly that the center was slightly concave. I continued this until the back was uniformly scratched by the sandpaper, indicating it was flat. I did this with both pieces of horn, as well as the pieces of Padauk that were layer in the handle.

The horn only needed one side flattened, since the outside would eventually need to be shaped. The Padauk would be sandwiched in between the horn and tang, so it needed to be flat on both sides. There is also a layer of vulcanized fiber in the handle as a spacer, so I cut two pieces of this to be the same size as the horn scales.

The scales epoxied to the tang and drilled for pins.
The scales epoxied to the tang and drilled for pins.

At this point I epoxied the scales on, sandwiching all three layers and adding epoxy to all the surfaces and clamping them in place. This is somewhat messy work, and it can be difficult to get everything aligned properly with all the epoxy. It may have been easier to epoxy each layer separately, but ultimately it worked well after careful clamping. I use a 2-part 30-minute epoxy.

Once dry, I drilled the holes in the scale using the holes in the tang as guides, then repeated the whole process on the other side.

Rough sawn handle.
Rough sawn handle.

Once all the epoxy was cured, I used a bandsaw to saw away as much of the excess handle material as possible, to minimize the amount of sanding and shaping required. After that, I installed the rivets (after the first failed attempt at using nickel-silver pins), and began shaping the handle.

This is all done freehand, working slowly on the belt sander and spindle sander, then moving on to files and the Dremel for more detailed work. The handle shape is ultimately a matter of preference, but I chose to keep this one relatively flat. It’s slightly tapered at the front and back, and rounded over on both the top and bottom. One trick to getting a nice even round over is to clamp the blade between two blocks of scrap wood in the vice, then using a long strip of sanding paper pulled back and forth over the handle using a downward pressure.

Once you have the shape to your liking, the final step is to finish it with finer grits until you get a smooth surface. Typically with wood handles, sanding up to 220 grit is more than sufficient. For the metal parts, I usually sand up to 1200 grit and then follow that with polishing compound on a buffing wheel. The best way to get a good finish on the steel parts is to alternate the direction of sanding with each progressive grit (usually I use 100, 220, 500, 1000, 1200). By doing this, you can easily see when you’ve removed all of the previous sanding marks by holding the knife at an angle to a light. In the case of the buffalo horn, I also sanded it up to 1200 grit and followed with the polishing compound, but unlike the steel, it’s best to only sand the horn with the grain, rather than alternate directions. Lastly, I put one coat of tung oil finish on the wooden portion of the handle and then buffed the entire handle with a soft cloth.

handle1.jpg

 

handle2.jpg

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The finished handle
The finished handle

 

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