1.11.2021 Shutters and base ring.

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 Monday 1st November 51F, largely overcast and windy.

I levered the outer shutter ribs upwards to make them higher. This almost closed the gap between the shutters. Screws were driven through the outer ribs into the bottom boards to stop them moving up or down.

I then loosened the bracket fixing nuts to allow more freedom in their slots. This helped to close the gap between the shutters. They can't close any further than when the shutter ribs are stopped by the slit ribs. 

The shutters open and close more freely and evenly now. The image shows the shutters wide open. They can pass over the slit ribs but are stopped by the slides. I may fit stop plates to prevent excess movement.

Next I shall complete the base ring while outdoor temperatures are still above the stated minimum. [45F.] With the daytime air temperature hovering around 52F. The forecast is for steadily falling temperatures. I may not get another chance for gluing until next spring. I have marked the ring arcs to avoid confusion.

I made two more arcs from 12mm Baltic Birch plywood to have plenty of spare material. Arranging the staggered joints and reversing the skewed joints on each ring is supposed to add strength but uses up arcs.

Completing the base ring proved to be more difficult than expected. Its height was intended to directly support the slit base board. Only when I propped up the arcs to form the ring did I realize that I had designed myself into an obvious trap. 

The dome steering wheels [vertical rollers] will crash into the base board. So the baseboard has to be raised even further. With spacers between the base ring and slit board for mutual support. I must not block the steering wheels track. Where they run on the inside edge of the base ring. The image shows the ring mock-up and how far it projects forward of the shutter drawer slides. The shutters have been pushed well outside the slit for ease of access. Stacks of bricks and timber temporarily support the ring.

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