28.09.2021 Bracket clearance from the dome.

 *

Tuesday continued: Following on from yesterday's discussion on the base ring brackets. That post was getting a bit long.

Today I arranged a triple layer of 12mm ply arcs on top of the dome rib to mock up the base ring. The shelf brackets was arranged with the long leg vertical.

The gap behind the shelf bracket increased to 16mm as shown! These shelf brackets are far too stiff to change their angle. Any attempt to do so would probably result in their destruction. They rely on the relatively thin section being reinforced by their pressed form. 

The image is slightly misleading because the bracket is being pushed inwards at the top by the dome curvature. Rotating the image, to capture this rotation, just makes the bottom leg look wrong.

I could make a strip of 16mm ply and kerf saw it to make it flexible to follow the inside curve of the dome. Or, a strip of 12mm ply standing on edge going right around the dome? 

Both ideas would offer advantages. Even support for the brackets and even resistance for the base ring against lifting. The brackets would probably adopt a slightly more acute angle when bolted to the dome. Though the considerable resistance from the brackets might force the base ring downwards.

A strip of 16mm ply could be tapered on its vertical axis on the table saw. This would fill the gap behind the brackets more efficiently than 12mm. The strip could even be glued down on top of the base ring. This would help to spread the upward loads on the base ring and increase its vertical stiffness. I'll ponder further on the possibilities.

 

 

*