More about the diaphragm stretching jig:
It took less than a day to draw up and build my 2-frame diaphragm install jig. I won't call it a stretching jig because the stretching is actually done by hand. The jig just supports the stator and provides curved surfaces to stretch the film over.
The jig worked better than I imagined, and it's not hard to build.
I used a table-jig saw to cut the curved frame sides out of 3/4 plywood, but a hand-held jig-saw would have sufficed. The inner braces are 1 1/2 x 3/4 pine planks cut to required lengths and screwed to the plywood frame-sides.
The jig has an inner frame that nests inside an outer frame. The stator rests on the inner frame, which has the same curvature as the underside of the stator, and same periphery dimensions.
There is 1/16" periphery clearance between the outer frame and inner frame. With the stator resting on the inner frame, the outer frame is level with the stator.
The outer frame's contoured sides correlate to the diaphragm-surface in the panel (i.e. front surface of
stator + 0.045" spacers). The outer frame edge-surfaces must be sanded smooth to prevent snagging and tearing the fragile 6-micron film when stretching the diaphragm. I covered these surfaces with blue painter's tape for added protection against snagging the film.
The outer frame can be lifted to allow sliding the stator out of the jig, from either end, without disturbing the pre-tensioned diaphragm on the outer frame.
There is no built-in mechanism to raise the outer frame. I just lift it by hand and place some wood blocks under its bottom corners to support it.
The stretching procedure is described in the write-up so I won't repeat it here. After removing the backing from the adhesives, the stator is inserted back into the jig and the tensioned diaphragm is lowered onto it and bonded.
I have a drawing of my jig that I will share if anyone wants it.
I should point out, however, that my jig may not be as accurate as it should be because I could not measure the panel's contour in the speaker (I only had the panel).
It would be prudent to measure the panel's contour in the speaker, and then revise my drawing accordingly.
Charlie
It took less than a day to draw up and build my 2-frame diaphragm install jig. I won't call it a stretching jig because the stretching is actually done by hand. The jig just supports the stator and provides curved surfaces to stretch the film over.
The jig worked better than I imagined, and it's not hard to build.
I used a table-jig saw to cut the curved frame sides out of 3/4 plywood, but a hand-held jig-saw would have sufficed. The inner braces are 1 1/2 x 3/4 pine planks cut to required lengths and screwed to the plywood frame-sides.
The jig has an inner frame that nests inside an outer frame. The stator rests on the inner frame, which has the same curvature as the underside of the stator, and same periphery dimensions.
There is 1/16" periphery clearance between the outer frame and inner frame. With the stator resting on the inner frame, the outer frame is level with the stator.
The outer frame's contoured sides correlate to the diaphragm-surface in the panel (i.e. front surface of
stator + 0.045" spacers). The outer frame edge-surfaces must be sanded smooth to prevent snagging and tearing the fragile 6-micron film when stretching the diaphragm. I covered these surfaces with blue painter's tape for added protection against snagging the film.
The outer frame can be lifted to allow sliding the stator out of the jig, from either end, without disturbing the pre-tensioned diaphragm on the outer frame.
There is no built-in mechanism to raise the outer frame. I just lift it by hand and place some wood blocks under its bottom corners to support it.
The stretching procedure is described in the write-up so I won't repeat it here. After removing the backing from the adhesives, the stator is inserted back into the jig and the tensioned diaphragm is lowered onto it and bonded.
I have a drawing of my jig that I will share if anyone wants it.
I should point out, however, that my jig may not be as accurate as it should be because I could not measure the panel's contour in the speaker (I only had the panel).
It would be prudent to measure the panel's contour in the speaker, and then revise my drawing accordingly.
Charlie
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