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08/04/2011 |
  
Joel,
Can your saw cut these?
Patrick Edwards
A few months ago Patrick Edwards sent a beautifully simple and beautifully hand written note to Joel along with a sampling of hand cut veneers. Patrick had thrown down the gauntlet and Gramercy accepted the challenge.
Veneer saw blades are beveled so they function sort of like a serrated knife. The beveled tips of the teeth are what cut the veneer. This is why a veneer blade with zero fleam and 45 degree rake ( on the Gramercy 15-90 blade) will cut; the razor pointed tips of the teeth slice the wood fibers. Beveled veneer blades work great on veneer under .030" thick. The sawn edge of the veneer looks almost polished, and it is possible to cut thin slices in fragile wood that a regular saw tooth would shred.
The samples Patrick sent were all within a couple thousandths of .050". That's a hair (literally) thinner than the thickness of a dime. In veneer thicker than about .030" the blade begins to wedge into the kerf before it can slice through the veneer. When using veneer .040" and thicker it can become quite difficult to overcome the friction created by the wedging action and continue cutting.
To mitigate the friction I developed a set of two prototype blades, named by Tim "Laurel" and "Hardy". Both blades were filed using 15-20 degrees of fleam, essentially a cross cut filing. Tim suggested a blade with raker teeth so Laurel (or was it Hardy?) was filed with a fleam-less raker tooth every third tooth. We did some in house testing, took some notes, and shipped Laurel and Hardy off for testing by Patrick Edwards and Patrice LaJeune at The American School of French Marquetry in San Diego.
A few weeks later I phoned Patrick and Patrice to discuss Laurel and Hardy. Both felt the blades were a step in the right direction but that neither blade tracked along a straight edge very well. Patrice suggested adding a bevel to Laurel and Hardy.
The point was well taken, as it had become clear how very dear to the functioning of a veneer saw the blade's bevel is. After our conversation I filed up a fresh blade with a 15 degree cross cut pattern, and gave it a small bevel about half the depth of a regular v-blade. It worked horribly, but tracked quite well. The problem was that the bevel annihilated half the teeth, and barely touched the others. This snaggle toothed pattern left only half the teeth in contact with the wood. It cut slowly, and wedged. Bah humbug!
I tried a few different filing patterns. Including some reminiscent of a wildly-sloped-gullet-prototype that some of you may have seen at Wood Working in America last year. With each successive blade I tried a smaller bevel until I had a cross cut pattern with a very light bevel kissing only every other tooth.
This blade tracked well but because of the relaxed rake cut quite slowly, especially when ripping. I upped the aggressiveness of the rake by changing the file attitude, and switched to a more sash-like fleam. This monster of a blade was sure to cut the thickest of veneer, so I markered on the prototype name "King Kong" and took it to the bench for testing.
King Kong nicely mixed the cut performance of an unbeveled blade with the true tracking of a beveled blade. The sash like teeth ripped and crossed equally well just like our Gramercy sash saw. I made a few adjustments to the rake, fleam and file attitude until it was just right, and then sent the blade off to Patrick and Patrice.
Patrick and Patrices gave King Kong the thumbs up. From there the only question was was whether or not this would be the one off answer to Patrick's challenge or a production blade. Joel, Tim and I talked about the feasibility of adding it to our product line. The result was the Custom Shop at Gramercy Tools. The Custom Shop will Gramercy's product line of carefully developed tweaks to existing Gramercy Tools. One of the things I'm excited about is that Custom Shop offerings will get to keep their prototype names. I'm very proud, as all of us at Gramercy are, to officially launch the Custom Shop with "King Kong," and a huge thank you to the folks over at The American School of French Marquetry. Patrick, and Patrice, your advice and criticism were invaluable. Merci beaucoup!
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