2020-03-23 (M) Electro Knife for Simulated Combat EleKSCo

I thought I was ready to build a handful of knives, but I was missing parts, but I got a start. I cut five segments from the mystery hardware store plastic, and I found that I can use my stepped drill bit to ream the inside of the tube cleanly. The pipe had some white ink or paint that listed the size and manufacturer, but I could scratch that off with a fingernail.

Internal reaming with a Unibit

The hole in each pipe needed a procedure to make them uniform. I put a piece of masking tape at the approximate location of each hole, then I lined it up with the existing handle, and marked the exact location. Each mark was pilot-holed, then drilled out to 1/4" (6mm). Finally, I used a stepped drill bit to expand the hole to 5/8" (16mm) to fit the switch.

Switch holes in pipe lengths

After I drilled the holes, I went to test how the switch and adapter would fit, and I discovered that the adapters I was printing were too small. I switched models at some point and forgot to expand the scale to 105%, which is a quirk of my printer. After I figured that out, I had to discard seven finished builds and one that was in the middle of production.

To fit the knife blades into the handles, I would have to trim them down, so I bought a 1 1/8" (29mm) hole saw. The internal diameter of the pipe was 1" (25mm), but the hole saw measures according to the outer diameter, so I had to account for kerf width. I tested on a scrapped handle, but it turned out that I wouldn't need to do this on a Cold Steel knife.

Modifying rubber with a hole saw

I trimmed off the handle from a Cold Steel knife with a hack saw. The finger guard was thin enough that I could remove it with a razor knife. I kept approximately 30mm from the back of the blade. The razor also had no trouble cleaning up the edges of the cuts so it would slip into the handle cleanly.

Shortened knife

When I pushed the trimmed blade into the handle, it distorted slightly, but it shouldn't hurt the performance or durability. A soft plastic handle may work best in this regard since I do not have to trim away as much rubber and further weaken anything.

Distorted but a snug pipe

GitHub repo for EleKSco.
The rest of the posts for this project have been arranged by date.
First time here?
Completed projects from year 1
Completed projects from year 2
Completed projects from year 3
Completed projects from year 4
Completed projects from year 5
Completed projects from year 6

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2020-03-10