DIY Knife from O1 tool steel

For quite a while I was looking for “the perfect knife.”  I wanted a fixed-blade hunter, but something that was a little more durable than you commonly see in that style.  At the same time I didn’t want something as clunky as a “bushcraft” knife.  My typical cutting tasks include carving wood, preparing kindling, dressing fish, and at home stuff like breaking down cardboard boxes, cutting rope, and scraping stickers off things.  I probably could have found a knife like this, but not in my price range.  Long story short, I decided to make my own.

I started by printing out several images of knives that I had found online.  I drew up some variations and cut them out of cardboard to see how they handled.  After a few iterations I ended up with a variation of the ENZO Trapper 95.  My design has a flatter heel and more angled blade in relation to the grip.  Also the blade is slightly longer.

A friend was kind enough to give me a 9″ piece of O1 tool steel 1/8″ thick by 1.25″ wide.  I traced my design on this and cut it out with my bandsaw.  I finished shaping with my homemade 1″x42″ belt sander.  For the bevel I cut a small piece of wood to a 13-degree angle and used it as a guide on the belt sander.  Some holes were drilled for a couple rivets, but also to lighten the handle for better balance.

To harden I heated the blade with an oxy-acetylene torch until it was no longer magnetic then quenched it in 130-degree peanut oil in an old meatloaf pan.  I heated the oil in the pan by putting it on a portable electric stove and used a kitchen thermometer to get the temp right.  My first try wasn’t successful – I was easily able to remove metal with a file.  My second try I realized I hadn’t gotten the steel hot enough and this time I paid closer attention to the color when it went non-magnetic and made sure it was uniform.

Once it was cool enough to handle I tried a file – it just rubbed on the surface and wouldn’t bite in so I knew I got it right.  I put it right into a toaster oven at 400-degrees for 2 hours to temper it.  A regular toaster oven won’t keep a precise temperature but I have a special setup.  When we got a new toaster oven I kept the old one and bypassed the controls, hardwiring it to on.  I plugged this into a controller I made which is basically an SSR (solid state relay) and PID controller that I got off ebay.  A K type thermocouple goes in the oven and the PID controller cycles the SSR to keep the temperature at the set point within a degree or two.

Finally I sanded and polished the blade on a water stone before sharpening it with my Spyderco Sharpmaker.  Having read all sorts of suggestions about how to heat treat O1 steel for knives I’m actually surprised how well it came out.  After sharpening I whittled some dry maple (a fairly hard wood), then batoned it into a 3/16″ brass rod.  I even made some glancing blows to the rod to try and make the edge roll or chip.  This did nothing to the edge!  I was prepared to do a second, maybe hotter tempering but I’m pretty happy with the way it is.

For the handle, I’ll be fitting some pieces of figured walnut that I have leftover from a woodworking project.

Dennis

A mathematician, hacker, fabricator, and all around do-it-yourselfer. I like building my own tools, learning new technologies, and breaking stuff.

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