I live in an area which produces some of the most beautiful walnut in the whole world. Along with other woodcraftsmen, I have grown to love and respect this fine claro walnut, as I strive to reveal the full beauty of the wood and grain patterns in my work. But as this and other fine hardwoods become rarer and more expensive, I hate to see such a large proportion of my wood end up as useless chips and sawdust. Laser technology should soon enough provide paper-thin cuts, but that day is not yet here. So for more than two years I have been searching for a high-quality, thin saw blade. And I believe I have found it.
A trip to Japan has long been on my wish-list, to study Japanese architecture first hand and hopefully meet some of the renowned Japanese craftsmen. This Spring I finally fulfilled that dream. In my week in Tokyo, I asked where the best tools were made. Invariably, the answer was Miki, a small town near Osaka.
Railpass in hand, I hastened to Miki, and was fortunate enough to run into an English-speaking international representative and distributor of fine tools. He befriended us and took us on a two day tour of the town’s tool companies, including a visit to one of the best chisel makers I have ever seen.
The Tsumura Blade
When I mentioned my long-standing need for a quality, narrow-kerf blade, my friend took me to the Tsumura Company which has developed a carbide tripped circular blade that is incredibly thin. As we toured the modern facility where the Tsumura blades are produced, I grew even more excited over this discovery.
The Tsumura blade in the 10″ and 12″ sizes leaves a kerf of 5/64 of an inch. These blades are particularly well suited for resawing stock with the saw and channeling the edges of wide boards for aid in resawing on the band saw. The Tsumura’s kerf is only half that of my thinnest blade, which translates as half the waste, and closer bookmatches. The narrow kerf also reduces cutting resistance. A small saw breezes through 2″ thick oak with a Tsumura blade.
I purchased a 12″ 40 tooth “rough rip” blade which I now use for 90% of all my cutting. It not only slips through the thick Butte County carlo walnut with ease, but it also crosscuts plywood more cleanly than my 80 tooth European panel blade!
Sharpening And Warping
The Tsumura rip blade features a slight alternate top bevel. The face bevel, combined with the reduced size of the removed chips, renders little potential for tearout. I have not seen this type of face bevel grind on any other carbide tripped blade; it makes a big difference in achieving a smoother cut.
There is no trouble in jigging up to resharpen the blade, and it takes no special equipment or extra time. I would caution you, however, to use a fine grit sharpening wheel and keep a light touch.
My initial concerns about possible bending and warpage with a blade this thin proved to be completely groundless. The sumura blade tracks as straight as any thicker blade I have ever used. The narrower cut and reduced friction cut down on heat buildup, and eliminate warpage. Yes, you can make the blade bend in a trim cut, with pressure on only one side of the blade, but if this is a serious concern, the Tsumura trim blade, about 3/16″ thick, will handle the problem. I have never needed the thicker blade in my experience.
More recently I have equipped some 10″ Tsumura blades. The 60 tooth crosscut blade exceeds the performance of any other blade I have tried on my Dewalt miter saw. It produces a “paper erdge” clean cut on all sides of my test pieces. The 80 tooth plywood blade produces a cut so clean it is hard to tell top from bottom!
This is NOT a specialty blade in Japan. It is a high quality, industrial grade tool that is now common throughout the Japanese woodworking industry. The blades are available in sizes from 7 1/4″ to 24″, with from 35 to 140 teeth. The larger blades are slightly thicker (3-4mm) but still very thin by Western standards. The power necessary to drive these thin blades is greatly reduced, and their light weight is an important factor in the durability of any saw.
I am very excited about this technology, and until the portable woodworking laser is perfected, I’ll stick with my Tsumura blades.