The Sword Geek

It's all about the swords. Except when it isn't.

A Blade Comes To Life

I had an idea for a cool knife of a type I had never seen before. The concept was a traditional Japanese Tanto Blade mounted as a WW2-era combat knife. The steep, short point associated with modern ‘tactical’ tantos was never actually used for these knives in Japan; I wanted a longer kissaki that was more reflective of the traditional style. I’d combine this with the simple steel fittings and stacked leather handle typical of American combat knives of the period.

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It starts out simple enough, with a Sharpy marker and a ruler. The most basic shape of the blade is laid out along with the tang. I always make the tang longer than I expect the finished handle- far easier to shorten it than it is to make it longer! Normally I would draw in and cut out the point, but for this style of blade I start out with a simple rectangle.

thumbnail_img_0131The blank is cut out on a bandsaw with a bi-metal blade with a 10-14 variable pitch. I finished rounding the join of the blade and tang on a belt-grinder.  Typically I will grind a 45-degree bevel on either side of the blade to establish the center-line that I will grind to. I usually leave a flat of .005- .006″ at the edge at this point. In the base of this blade I also bevelled the back to leave a flat approximately .150″ since the blade will be ground Shinogi-Zukuri, a diamond section that is flattened at the spine.

thumbnail_img_0132Here the bevels have been flat-ground to produce the desired cross-section. I grind first at 60-grit, then refine it at 240 grit. I often finish at 400-grit or polish on a sisal wheel, depending on the desired effect. Since the look that I am going for is a military combat knife from WW2 I ground perpendicular to the edge to produce fine lines that will work well with the blued finish. I returned to the band-saw to cut the point to the desired angle, then flat-ground the angles to the point to produce the kissaki, or point-bevels.

thumbnail_img_0134The Kissaki is ground. The blade is then heat-treated. I won’t go into exact details here, but this is done in a gas forge. Naturally the thinnest portions heat up the fastest, so the edge gets up to hardening temperature more quickly than the rest of the blade. If I manage the heat properly I can quench it before the body of the blade reaches hardening temperature and wind up with a hard edge and a softer, tougher body of the blade.  To some degree this mimics the traditional tempering of a Japanese blade, though with 5160 it does not produce the sharply-defined temper-line that one can achieve with clay-tempering.

After heat-treatment I round the edges of the tang, then cut a reduced section  for the 1/4-20 thread that will secure the butt-plate.

thumbnail_img_0135The blade is now polished on a sisal wheel with Black Stainless rouge. The guard is cut and ground to shape, then drilled and filed to produce a tight fit on the tang. The guard is relieved to accommodate the curved shoulders. In the lower-right of the picture is the piece of 1/4″ plate that has been bored and tapped with 1/4-20 thread to screw onto the end of the tang.

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The picture above shows the process of making the stacked leather handle. I use a strip-cutter to cut several strips of 6-7 ounce top-grain vegetable tanned leather, then cut the sections to length and glue them together with contact cement two at a time, then glue those together. repeat until I have a block of sufficient size for the handle. I then coat the block with a penetrating acrylic finish; essentially a super-thin cyanoacrylate. This makes a nice, solid block that I can clamp together in the vice on the drill-press and drill exactly as if it were a wooden handle. The finished handle is then force-fit onto the tang and ground to shape, then receives another coat of acrylic and is buffed to finish the handle.

img_0144The blade was then polished to a sharp edge, and the blade and fittings were finished with Van’s Instant Blue. The knife was assembled with epoxy for permanence. I placed my maker’s mark and the serial number on the spine of the blade so that it would not interfere with the finished appearance of the knife.

At some point in the coming winter I’ll actually have a photographer in to do a more detailed knife build; this is pretty much the best that I can do at the moment since I cannot photograph myself working…

November 21, 2016 Posted by | Podcast | Comments Off on A Blade Comes To Life