5/29/16 part II
I tested the fit after planing. It slid nicely with minimal slop.
I waxed the runners anyway to help it slide more easily.
I screwed the L brackets down to lock the frame in place. The plans call for a lot of screws because there will be a lot of force pulling against this frame. I used good structural grade screws. Then I took the bearing block and placed it in the frame and clamped it there to check the alignment.
I used a framing square to be sure the top and bottom shafts were square with the frame before I held the block in place with a couple little drywall screws. The drywall screws just keep the bearing block in the proper location. The frame holds it securely in place when blade tension is applied.