As one is clamping the blocks and ribs into position, be sure that they are all above the mold surfaces on both sides. The pictured 'checking block' is for checking installed block height. Notice the notch cut out for rib clearance.
Notice that the blocks and ribs stick up above the master mold surface.
These will be trimmed in two stages. The first will leave the blocks and ribs about 1/16" high. The rib liners will then be glued flush to this new surface height.
In this view, I have bolted on 20" long flat steel guide rails and 5/8" square by 20" long cross bars. and am using a dedicated router with a 1/2" flat bottomed carbite cutter to machine the edge surface flat and paralled to the guide rails on this side of the exterior master mold..Do this in two passes.
Next, the guide rails are removed and all the clamps transfered, one at a time, to the top side. The mold is then flipped over so I can machine the other side.
To help get a good machined surface on the blocks (which are made of spruce), it is helpful to spray the end grain with a mist of water before machining. This helps prevent splits on the edges of the blocks. (Wipe excess water from the surface with a rag).
Modified 9/2017
Page O16C_19
