mouse over blue lettering to see photo
The bearing recess was made 0.002" smaller than the bearing thickness to allow the cover plate to firmly secure the bearing.

Top cover plates were round, while the bottom plates supported the worm part of the drive gear assembly.

The top of each shaft was flanged to mate with the bearing while the bottom was secured with a shaft clamp to eliminate shaft play.
Shaft Enclosures and Bearing Supports
The shaft enclosures were fabricated from 3" id  by 0.125" wall aluminum tubing.  Ideally, the shaft bearings should fit inside this tubing, but 55mm id bearings with a 70mm od are non-standard and almost four times as much as the 90mm od bearings used. The bearing holders were made from 1.5" plate attached by threading the inside of the tubing, (24tpi) and after final adjustments, epoxied together.