Thursday, November 11, 2010
An update (this is a revised version).
What's been going on with old John? This week has been sawing, sawing, sawing. It is also goodbye to couple of old friends. I have two, very old jeweler's saw frames that I had to retire. After repairing them numerous times, it became impractical to do so anymore. The metal which the frame was constructed was a strange kind of alloy. I had encountered it only once before. I'm just guessing that it was a kind of bronze. Anyway, the wear and tear of unloosening the thumb screw, wore out the threads. It meant drilling out the worn threads, re-tapping threads and replacing the thumbscrews, only to go through this again, and again. Now, they are replaced with new, modern saw frames.
So now to the sawing. I bought several 12" x 12" sheets of copper, brass and nugold (bright brass), and have been sawing them down to what for me are workable sizes. Since my bench shear has only a 4" capacity, the sheets have to have one, 4" dimension.
To saw the sheets, I took a piece of Baltic birch plywood (about 18" x 24"), and marked out a 6" x 6" square in one corner of the plywood, extending one of the lines across the 18" dimension. Then drilled a 3/16's" hole in the corner of the square where the lines intersect.
That's relief for the saw blade when unloosening it from the saw frame. This is necessary when the saw frame's throat is only 5 7/8's inches. The using an electric jigsaw and a guide, I made a saw cut along one of the lines from the edge of the board to the hole.
This layout allows all around support for the metal sheet. You don't want to have the sheet extending outside as it will vibrate from the sawing and cause gloom, despair, and agony and break saw blade after saw blade.
I marked out 6" x 6" rectangles on the sheets with rule and scriber, and drilled a hole in the metal sheet where the lines intersect. Lining up the scribed line with the saw cut and the extended line, I taped the sheets to the sawing board with blue painter's tape. I have to do this to secure the sheet to the board. Otherwise, it moves around too much. Then began sawing. I took the 6" x 6" and cut those down a little smaller, leaving a 6" edge on some in case I might need that length for a project. Dressed down the sawn edges with 320 grit paper on a sanding stick, marked the gauge on the pieces, wrapped them is salvaged packing paper, put them in a ziplock bag, marked with the gauge and type of metal.
All this may not be economical for some. Since I don't make jewelry as a main source of income, the time used really doesn't matter.
Til next time, John