The normal Aeolian rocking double acting motor pneumatic has the movable leaf hinged to the fixed side with a thick strip of vellum inserted crosswise in saw cuts in the center of the leaves.  This normally does not have to be replaced during rebuilding.  But in this form, the movable leaf between the the two fixed sides is hinged vertically at the bottom, in a way that must be unique.  Like all the rest of the pouch leather in the organ, I wanted to replace it.  The method I figured out to do this might be of interest.

    Start by splitting off the rear leaf, which is glued and screwed to the front with two little "ear blocks".  Some of them split, and ended up partly stuck to the front piece; these remnants were pried off and glued back together on the rear piece.  All the old glue was washed off, and each piece marked so they went back together in the right order.  The tapered edge of the moving leaf was masked, and new cloth and leather glued on.

    The old tack strips broke coming off, so new ones were made, a little overlong and over thick, and glued to the free end of the hinge flap.  Glue on the stick with the flap bent up as shown, otherwise the stick will be too close to the edge of the leaf, and the hinge will not be flexible enough.  I learned this the hard way, by doing it wrong the first time, and had to do the hinge flaps all over again.  The excess inside was trimmed along the masking tape line, and the flap was trimmed to the lower edged of the tack strip.

    Now the moving board is glued and nailed into the little rabbit where it goes.  The nails are countersunk, and the face of the stick is carefully sanded so that its front face is even with the plane of the lower part of the main block.  This is the surface where the ear blocks are reglued, and it must be flat.  While I was at it, I applied fresh hot glue to all the end grain surfaces  and passages in the main block.  It is made of mahogany which is very porous, and all these surfaces were originally sealed with glue.

    Now the moving leaf and the fixed leaves are aligned, and the rear leaf is glued on, around the edges of the ear blocks and along the bottom edge.  Originally 1/2" #4 screws were used on the corners, probably only to hold the joint together until the glue dried.  But such replacement screws wouldn't hold, and tended to split the wood, being so close to the corners.  So clearance holes were drilled down through the thin bits, into solid wood below, and new 1-1/4 #4 screws were put in after the glue had firmly set.  Then, when everything is fully dried, carefully sand of the excess length of the tack strip, and make sure the edges of all three leaves are on the same plane.  I hate to use the sander on this job, but here is a case where it seemed unavoidable.  One must be careful that the canvas and leather comes all the way out to the outer edge at the hinge line, so a seal is formed when the cover is glued on to that tiny point.

    Now the center leaf should flap back and forth between the two outer boards very freely, and there should be no openings out of the rear pneumatic space except through the oblong passage at the bottom, to the lower valve hole.  Ready for recovering.

[back] [forward] [index]