Rear rail and bottom panel in glue up fixture.

Novena Heirloom – sawing to height

One of the tasks for which the vacuum table was created was trimming the upper edges of the bottom panel to proper height for mounting the front and rear rails. The rear rail also serves as a mounting location for the hinges. For reasons examined in an earlier post, the rear rail must be mounted slightly proud of the top surfaces of the aluminum side plates. A subsequent operation entails sawing to height to match up the rear rail to the side plates.

Rear rail, side plate and hinge mortise
Rear rail, side plate and hinge mortise

The image above shows the side plate loosely inserted into the bottom panel assembly. When the side plates are finally installed, the clamping pressure will align the adjacent wood and aluminum surfaces. The aluminum side plate slightly overlaps the wood composite everywhere except at this top location. The proper fit posting discusses how this fitting is done.

Rear rail and bottom panel in glue up fixture.
Rear rail and bottom panel in glue up fixture.

To make this work out properly, the rear rail mounting location must fix the rail in the correct position to allow for the fitting process. Measurements are made to determine where this height is along the back edge of the composite bottom pan. Then the part is set up in the custom vacuum table and trimmed to size with a 72 tooth slitting saw. Downhill cuts are made on both composite surfaces to prevent tearout or splitting of the veneer.

The video below shows the sawing to height operation on the CNC mill. Note the dual passes to create a downhill cut that prevents tearout in the composite surface veneers.

 

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