18.01.2021 Studs for stiffer stays.

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Tuesday 18th 40F.

 My need for a stiffer stay for the top channel has been answered. I shall use an M10 galvanized stud [threaded rod or all thread.] This is the same size of the galvanized bolts holding the dome segments together. If the 10mm proves inadequate I can increase the diameter to M12.

The bottom of the stud can be bent to pass through the dome joint perpendicularly. Similarly at the top, if needed, to pass though a hole in the channel. Galvanized nuts will clamp where necessary. With a large, stainless steel washer and rubber tap washer sealing the dome as usual. 

The bare, threaded section, in the middle, can be sleeved with an aluminium tube for neatness. With luck it may even provide some extra resistance to compression loads and bending. 

The top fixing, in the channel, is well beyond the outer travel point of the skate wheels. Should the shutter overshoot [highly unlikely] it can be safely stopped here. The advantage of studs is easy adjustability for channel level. Whether the perforated strip stays will still be required I shall only discover when the studs are in place.

The image at the top of the page shows the first threaded stay. Putting a bend on the end of the rod required considerable effort. These threaded rods are stiff!  The result of adding a compression stay was a very rigid assembly. I tensioned the perforated stays until they rang on being tapped.

Now for the stays on other end of the channel. Done in a flash! The channel feels rock solid. I shall leave it until tomorrow, and daylight, to test the shutter movement. The lower channel has yet to be fixed to the base ring.

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