Ladder Fixture directions (Cont'd):

"The plastic blocks are fastened in place by two flat head Allen screws. There is a drill bushing 3/16” by 3/4” by 1/16” (actually .188” OD by .750” by .063” ID ) pressed into each plastic block.

The drill bushings allow the locating (shot) pin to register the ladder side rail as it is being slotted for the steps that will be cemented into the side rails at assembly of the ladder. There are slots at the 26 degree angle to accomodate the shot pin and to clear the milling cutter as it goes across the side rail. The 26 degree angle can be changed to suit any ladder you will be making.

The locating pin was made from a drill blank 1/16” by 1 9/16” with a .037” by 1/8” locator ground into the front of the pin. This pin engages the slot cut into the side rail and maintains the spacing between the steps. In use, the Fixture is put in a vise with a rotating base, or screwed down to a workplate which is fastened to the rotary table. If you have neither, you can put the Fixture in a plain vise set at the angle you need. Or, you can clamp the Fixture down on to the milling table at the angle required. Once set up, the operation is straightforward. Use a short piece of scrap for the set up piece. Clamp the piece down, and cut the first slot. Move the piece in the slot until the locator pin engages the slot you just cut.

The spacing is determined by the distance you have the cutter from the centerline of the locator pin. The .037” diameter of the front of the locator pin was arrived at by trying until I have a situation where the pin actually wedges on the bottom of the slot (in the side rail) and acts as a clamp. Since the Fixture slot is open, there is no limit to the length of the side rails you could slot and subsequently cut to the desired length of the ladder you are making. The reason for the two positions of the locator pins and bushings is because there are left and right side rails required for any ladder...This Fixture was developed to insure accurate and consistent results. "

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