14.12.2021 Shutter slide materials.

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Tuesday 14th 41F, early cloud eventually cleared to watery sunshine. Brighter still after 12.00. I had a look at the sun in the 90mm with Lunt wedge. One spot was visible in the cloud dimmed image. The plywood dome is growing tiny mushrooms all around the base ring!

I gathered together my scrap aluminium, box profiles to see what can be done. Apart from the 35mm channel I have useful lengths of 50x200mm, 70x70mm, 100x200 and 120x120mm. All external dimensions. Length-ways cuts can convert these box sections into useful channel sections.

The 50x200mm can become the bogies when cut along the middle of the longer dimension. To form deep, but narrow channels. The skate wheel is shown within the various profiles for scale.

The 70x70 profiles can be channeled to house the bogies. With the 120x120, again cut into channels, to support the whole lot and connect solidly to the shutters. Having a middle sized profile will allow fine screw adjustment for level and height. The shutters are very sensitive to these parameters. I am saving the lengths of 100x200mm for the planned, cross-axis, English style, equatorial mounting.

Axle clearance is an issue which needs careful consideration. Skate wheel axles use flat headed screws into a central, axle unit to avoid protrusions. I may be able use this system to advantage. All of these channels offer reasonable, lateral clearance between each other.

 

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