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Old 05-29-2015, 11:07 PM
charles Tauber charles Tauber is offline
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Quote:
Originally Posted by Viking View Post
Thanks Charles. Lots of ideas. I don't suppose you have a picture of the 2 minute fixture you use with a block plane?
The fixture consists of two pieces of plywood and two or more 3/16" x 3" (#10-24 x 3") machine screws and accompanying washers and wing nuts. Holes are drilled through the two pieces of plywood and the screws inserted through the holes. The screws accomplish three things. First, to align the two pieces of plywood. Second, to provide depth stops for how much the braces protrude from the top surface of the fixture: the braces sit on top of the screws. (Multiple holes can be drilled at different locations to accommodate different bracing heights and/or protrusion.) Third, to clamp the fixture and braces together.

Multiple braces can be planed at once by clamping them side-by-side in the fixture. The length of the fixture must be as long as the longest brace to be arched: the fixture does not allow braces to extend beyond the ends of the fixture, contrary to the photo below.



The top surfaces of the two pieces of plywood are shaped to exactly the desired curvature of the braces. Each piece of plywood is marked with the longitudinal center of the arch and the center of each brace is marked on the braces and aligned to the mark on the fixture.



The entire fixture can be secured in a vice while a block plane is run back an forth over the surface of the braces that project above the arch of the fixture.



The plane runs in a "track" cut into the top surface of the two pieces of plywood.



The width of the track exactly matches the distance from the edge of the plane's blade to the side of the plane. The track is contoured to the same curvature as the top surface of the plywood. A second "track" accommodates the width of an additional brace. A little wax on the contacting surfaces of plane and plywood allows for a very smooth action. One continues to run the plane back and forth over the projecting surfaces of the braces until the plane no longer removes wood, at which point the brace shaping is finished and ready for gluing.



As necessary, the direction of planing can be reversed, generally, working from the center towards the brace ends for bulk wood removal.

An improvement to the fixture is to add spacers to the bottom of the fixture the same width as the stack of braces being planed. This would prevent the fixture walls (plywood) from angling when the screws are tightened.
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