Step 14: Mark & Drill Screw Hole Locations
Determine locations for three equidisdant screw holes on one bearing plate with a protractor. Place a pencil mark every 120 deg and 1/4" in from the circumference. Use this disc as a template to locate holes on the remaining bearing plate as well as on the inner and outer end plates. Making sure shaft holes of each disc serve as the common center. Drill holes where marked to accommodate #6-32 machine screws, flat washers and wing nuts (later replaced by hex nuts in Step 21) .
At this point, glue one set of inner plates to one set of outer plates. Repeat this procedure with the remaining set of plates. Use the machine screws to secure these assemblies until dry. Do not glue retaining rings to plate assemblies!