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Monday 10th 43F. The aftermath: My anemometers are hardly turning this morning and the trees are quite still for most of the time. With occasional rocking to violent gusts. The wind was highly variable for the rest of the day. Alternating between noisy and powerful gusts and relative calm.
I spent the morning undoing all my paranoid changes in the observatory in readiness for yesterday's storm. Not too much collected rainwater in the sandwich boxes and the observatory floor and desk were completely dry. Thanks to the shelter belt of trees to the west it was mostly, quite peaceful in the dome today.
I did some calculations to try to work out the thread used on the Beacon Hill worm drives. No standard thread reared its ugly head, but M27x3 would match the smaller wheel. While 1" BSW worked close enough for the larger. These are only guesses and may be in error if the machinist used his own pitches rather than hobbing.
I sprayed the previously hand painted, baffle tree with matt black paint. Just to fill in the bare streaks from the cheap paint brush I had used earlier on the water based paint. I did the spraying outside in the lee of the workshop. To avoid inhaling the strong, petroleum fumes without spraying into the wind.
Next I painted the plywood countercell of the new, 6" H-alpha telescope. Otherwise it might never be done. Just like the 7" cell wasn't painted until very recently. The appearance didn't really bother me too much. It just looked a bit sad, amateur and unfinished in the photographs I shared online.
Both counter-cells are now painted matt black to match their lens cells. I also sprayed the inside of the 6" main tube from both ends. Also the inner face of the heavy tailpiece I had turned in the lathe.
After that I finally sawed off the spare [unused] crank on the top dome drive sprocket. Then turned the sawn crank stub smooth and round on the lathe. Slowly and gently, to avoid the hammering of the highly eccentric work piece.
I added two timber packing blocks under the [lower] drive crank support plate to stiffen it up. It feels much better as the crank is turned instead of being a bit floppy. Having tested the result I shall make a smart, new, single, packing block from larch cut-offs. With matching holes bored for the crank plate fixing screws and the [bicycle] bottom bracket axle.
The counterbalanced, friction wheel drive has worked well beyond my expectations. With a perfect [gear] ratio between speed of dome rotation and almost effortless cranking. Instant change of direction too. With easy acceleration up to speed for a rapid change of shutter orientation. Or just crawling around as required.
The secret to success was placing the friction wheel on the short end of a long "seesaw." With a 5kg weight on the far end to provide plenty of self-adjusting, upward pressure at the friction wheel. A fixed drive wheel would never have worked without a perfectly true base ring. While too much vertical movement would have played havoc with the chain drive. Which I added later to bring the crank down to within easy reach. While seated at my imaging, computer desk.
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