To make the Ladder Fixture, I took a piece of aluminum and machined it to 1/2” by 1” by 4”. Actually it is .500” by 1.000” by 4.000”, plus or minus .005” in all three dimensions. The reason is that in case, at a later date, I have to add something, I just put a scale (6” rule) on it and know it is a nominal size. That way I don’t have to take anything apart or spot holes etc. There are four mounting holes for the Fixture.

The fixture can be held in a vise, which rotates for angular setup. Or you can mount a work plate on the rotary table to do the same thing. I then machined a slot in the face of the 1.000” width that is a close fit for the side rail of the ladder I was making. The fixture can be made to accommodate any size rail and I therefore consider it a Universal Fixture. The slot in the Fixture is .210” wide and .072” deep. The slot is central to the 1.000” width, so the lands are .395”.

That is not critical to the use of the Fixture, just good toolroom procedure. Two angular recesses ( these were at 26 degrees) were cut across the .500” dimension to provide a mounting surface for the Plastic (“Lucite”, “Plexiglas”) blocks 5/16” by 11/16” by 3/4” ( actually .312” by .687” by .750”).