Selecting the depth of the reveal is partly for aesthetic reasons and also for a simpler build out process. I hinted at these reasons in a prior post about updating the Edison lamp prototype. Probably the first 5 versions of the lamps I built were similar to the prototype. Since then, I’ve set the Edison lamp top about an 1/8th of an inch lower. It’s a minor change but it has significantly reduced the number of times that I’ve had to rebuild a lamp – frequently the corner of one of the pins would chip out when routing the channel for the top.
By lowering the top a fraction of an inch, I’m able to route the front and back of the lamp without using a plunge cut. On the sides the plunge cut is still required. Basically what I’m doing is dropping the lamp side down on top of the router bit. The photos below show the result of the plunge cuts. The first photo shows the result of two plunge cuts and a little clearing between the cuts. Technically a single cut on each side would be more than enough, but I’ve taken the belt and suspenders approach. To make sure that I don’t extend my cut too far, I clamp a stop block to the router table fence.
From there I’ve flipped the side over and drawn lines on the top of the lamp sides. The lines are shown in the second picture below. I align the marks with router table fence where the cuts start and stop. In the picture the left side of the piece is complete. From here I repeated this process of plunge cuts and marking the sides on the right side of the piece. Finally I remove the stop blocks, plunge the piece over the existing cuts and then route the piece between the plunge cuts on each side.
This whole process takes maybe 15 minutes to complete properly, but any missteps can result in having to start the entire build over again. Thankfully by dropping the top a fraction of an inch, the number of rebuilds has dropped to zero. Final picture below shows the end result – the latest single bulb koa Edison lamp to leave the shop.