12.01.2022

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 Wednesday 12th overcast and misty. 

 I have been mulling over the fixing of the bogies to the top shutter boards. The idea of using the axles as fixing points makes much less sense now I have had time to think it over. It would involve detaching wheels, bolts, nuts and spacers. All in a very inaccessible situation high above the ground. 

 Far better to have the bogies detachable as complete units. To be worked on in comfort on the bench. Where the components can be dismantled if needed. Without loss of vital parts requiring further construction.

 The bogies would need to be lifted upwards to clear the channel for maintenance. So I need bolt fixings from fixed nuts. T-nuts are only available in coated steel. Which would be corroding before they even left their costly bubble pack. 

 I need some other form of furniture assembly nuts. Preferably in brass, aluminium or stainless steel. Time to do some more online homework.

 That was easy: I found these sturdy, stainless steel, M10 fixings. Used for holds on outdoor, artificial climbing walls. Cheap too, compared with online, fixing specialists at 10x the price! Duly ordered. I'll fit them from the inside of the boards. Then the fixing bolts will be trying to pull them right through the 24mm thick, plywood boards. Which would provide as much retention as desired.

 I spent the morning swapping the plain nuts over to Nyloc locking nuts. I find it is always best to wait until fully satisfied with an assembly before using locking nuts. Otherwise it wears out the locking mechanism. It also causes endless delays if something has to be repeatedly dismantled and re-assembled using tools. Instead of finger tight, plain nuts.

 The lower bogies are proving difficult to align and simultaneously achieve the correct shutter height. The lower ribs drag on the dome when there isn't enough clearance. The lack of concentricity is obvious to the eye from the outside. Though not remotely obvious when working on my hands and knees on the lower inside of the shutters. 

The shutters swing outwards from the pivot point at the top drawer slides. Gaining more height involves pushing the shutters outwards and lowering the bogies on the ribs. Each end requires a different height to make the 3D spherical shutters concentric in all planes.

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