Author: huboboe
Date: 2011-04-13 05:14
H.F. - First, the blade and guides (IMHO) need to be the same radius. If you put a smaller radius blade into your guides, only the nose would cut on the first pass. then the edges would prevent further cutting. If you put a larger radius blade into the guides, it would make a cut such that the rear guide would no longer be in contact with the cane. I think of the blade and rear guide as if it were a horizontal shaft, with the nose of the shaft angled and sharpened to scoop out the interior of the cane and ride upon the cut surface. (The front guide adjusts as described above).
There are only four 'knobs to fool with': two for set up and two for gouge adjustment. Gather 'round, chillins'...
For set up, with the blade off, adjust the front guide so that it is flush with the rear guide. (I lay a yellow pencil along the guides.) Then mount the blade and adjust it so that it just cuts the paint on the pencil. This makes the blade and rear guide resemble the sharpened shaft described above.
Now raising the front guide slightly will increase the chip thickness. As you gouge you can optimize your chip stroke by stroke.
You are ready to gouge. Drag the carriage slowly backwards through the bed in the fully down position to be sure the blade clears the cane stops.
With a single radius gouge, gouge one piece to completion without turning it. Measure the gouge thickness at the bottom of the cut. Adjust as necessary to get your desired thickness. Measure the sides. Adjust as necessary to center the blade. Gouge another piece of cane. Tweak your thickness and sidewall adjustments to optimize your gouge. Turn your cane end for end to insure symmetry.
For a double radius, do everything as above, but adjust your sidewall thickness to your desired dimension on the thin side of the gouge. When you turn your cane end for end you will get the same sidewall on the 'thick' side.
To arrive at 45-60-45 with a single radius, size on size cane radius and blade radius should result in those dimensions, or something close to it. (11mm on 11mm, 10.5 on 10.5, etc.) For a double radius, you will need to play with a couple of pieces of cane until you find the sidewall that compliments the center thickness.
And I (once again) assume the 'gouge thickness' of a double radius gouge refers to the thinnest part of the center gouge, not the central spine. Though I will hazard a guess that, with the additional mass of the 'spine', the 'center gouge' can be a tad thinner than .60. We'll find out by doing.
Lastly, the guides are mounted on the carriage with dowel pins and the distance from the dowel pins to the bottom of the rear guide is constant, so swapping blade/guide guide assemblies from single to double radius and back should make very little if any difference to the gouge thickness. BUT - swapping from double to single radius will require some attention because the double radius blade is offset, and the larger, single radius blade might crash the edge of the cane stop on the 'thin' side! So use care and center the carriage first with the double radius blade. Then finish gouging that piece with the single radius blade and all will be well.
When you sharpen the blade by honing the flat side, you will shorten it by only .6 of the amount removed from the flat by sharpening. This means that, until you have sharpened the blade several times, all you will need to do is remove, hone and replace the blade without touching the other adjustments and you will be gouging the same dimensions. As the blade becomes shorter, a tiny tweak om the mounting pin adjustment will compensate and a single trial piece will allow you to regain your chosen dimensions.
I went to my local plastic store and bought a series of colored circles (is that 'coloured' in Canada, Robin?) at 1 inch to the mm. I bought enough circles to photograph 11 0n 11, 10.5 0n 10.5, 10 on 10 as well as 9.5 and 9 doubled on 11, 10.5 and 10. I'll start a new thread with photos of these tomorrow and we can see if anyone has further contributions to the ongoing question: what's a good blade radius and offset to pair with a given cane diameter?
Robert Hubbard
WestwindDoubleReed.com
1-888-579-6020
bob@westwinddoublereed.com
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