Friday, June 27, 2014

Tanto woodwork

Well, after about a whole year during which the day job(s) took completely over, here we go again.
This is an older stock removal tanto that I had never gotten to finish. Following the instructions in Walter Sorrells excellent videos (order them if you haven't got them, otherwise check out his channel on youtube), I carved the shirasaya out of white poplar, a very light, easily carved but still solid white wood.
After gluing the pieces together, it turned out that there was a 4mm gap between the two. So I added two iroko hardwood spacers, which add some more strength to the mouth of the saya, and allow me to shape the mouth exactly as I want (i.e. hiding previous imperfections). The dark wood also complements the overall appearance.

Now its time for endless minute grinding and fitting...

Sunday, May 12, 2013

Wootz update - one failure and two successes!

The wootz project started some years ago recently got a new kick start. In cooperation with some other bladesmiths, we tried to forge the wootz ingot from the 2011 post. Unfortunately it cracked, and probably cannot be saved.


So we went back to the drawing board, so to speak, and came out with another two recipes, using the readily available materials here. One is with CK60 steel and grey cast iron, and the other with 52100 steel and grey cast iron. We also worked out the slow solidification by ramping the gas down gently, and here are the results. I have no idea how they will forge, but this looks like jewel steel!

 Next step will be to try melting iron or steel with pure carbon, in a sealed crucible this time...

Friday, April 5, 2013

New portable forge

I decided to construct a small portable forge to be able to work at home or away from the workshop. Its built out of an Illy coffee can, diameter 20cm, length 30cm. Lined with 5cm of refractory blanket.

I also tried to make a smaller propane burner, instead of the 3/4 inch Zoeller sidearm burner I use on my larger forge. This one is made out of 1/2 inch pipe, with a 0.6mm gas tip. I had some trouble making the air inlets without a drill press, and I will probably have to go to a machinist to drill them properly, but for testing they suffice. The rules of thumb for such a burner are a length at least 9 times the diameter of the pipe, a flare at the end, and an air inlet area equivalent to the opening of a 1 inch pipe.

After some tweaking here is a first acceptable flame. The good thing is that this type of burner runs well even on very low gas pressure. Also the 0.6mm tip used instead of the 1mm for the 3/4" sidearm burner should keep gas consumption to about 1/3 of the larger burner, which will mean much lower running costs. I should also built a sleeve around the air inlets to be able to control air intake and oxidizing-reducing burn.

On a first test the forge went up to 920C in 1-2 minutes, but I still have some doubts as to how well the forge will handle such heat. More testing will be posted shortly...

Friday, March 22, 2013

Proper Japanese style hammer, at last.

A friend made me a gift, a machined hammer head, made of Uddeholm Hotvar steel, which I finished, heat-treated and made a handle for.
Its 4.3cm wide, 13cm long, with a 34cm handle made of an old oak plank. Weight of hammer head is 1310gr, and together with the handle 1490gr. Perfect!

What was particularly interesting was the heat-treatment. Heat up to roughly 1000C, quench the first 5cm in soapy, warm water for 30 sec, and then let the heat of the remaining piece dissipate and do the tempering.

Tuesday, March 19, 2013

Athame finished!

Finally finished the athame! A note on materials, the wood is iroko blackened by burning it, in the Japanese sugi-ban manner, and the steel (such as it is) was tempered for 1 hour at 320C to get the blue-black oxide.

A big note on mystery steels! Don't use them! 
At least not unless you do a quench test, which I did not. Hence, the old handmade rasp I had found, turned to be unhardenable, though I tried both oil and water quenches. For this particular piece its no big deal as it a ceremonial item and will not see any cutting use, plus the 320C temper would have softened it a lot anyway. But still... its a shame.

Anyway, another lesson is that when I do decide to make a proper knife shaped like a yari, I will run into countless problems keeping it straight in the quench. This one took a wild upward curve, which I removed easily since it did not harden, but I really do not know what I would have done otherwise. In any case enjoy!