Main Runner Construction & Dimensions

"I am going to give you the dimensions and a brief description of the construction of the Main Runner first. If anything is not clear, I can try to steal some time, and make a sketch of the part in question.

Take the Main Runner, and drill two holes through the 3/4" dimension, one at each end.( the holes are clearance for the Flat Head Cap Screws. 3/16" Dia. will do). The holes are located 1/2" from each end and centered on the 1 1/2" dimension.

Now countersink the holes for the Flat Head Cap Screws from what will be the top of the Main Runner. Go deep enough so that the screws are flush or slightly below the top surface. Next cut two 1/4" slots centered on the 1 1/2" dimension. One on each end. The slots start 1 5/16" from each end, and are 5" long.

While you are set up , cut two runners for the slide blocks that will be 1" wide by 1/4" deep. The runners are at the top of the Main Runner surface.   The runners (or guides) start at each end of the Main Runner, and are 7 3/4" long, depending on the diameter of the cutter you use. 1/4" or 5/16" is OK.

The 7 3/4" dimension is at the outer edge of the Main Runner, where the cutter runs out of material while cutting the 1" wide guides.  Now turn the Main Runner over. Locate your spindle directly over the center of the 1 1/2" dimension that runs lengthwise.

Cut two slots with a 3/8" end mill that start 1 1/16" from each end and are 5 3/8" long. Make the slots 5/ 32" deep. Now you have counter milled the slots to allow the tee nuts ( along with the Flat Head Cap Screws, and slide blocks) to run along the Main Runner, and provide a means to clamp the slide blocks in place, during the use of the fixture.

That is it for the Main Runner."