Mounting update: Descent and Drives:

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Sunday: First of three days, in series, with all day rain and wind forecast.

Tuesday 28th Nov: A wet start but a pause allowed me to rig up the chain hoist to bring the heavy mounting down. It was easiest to lower it down through the stairwell with the ladder removed. The mounting had been sitting on the observatory floor gathering rust and lacewings under its multilayered covering.

I need to construct fine adjustment for the drive worms. This will give me something to get on with when the weather isn't ideal for outdoor self-amusement. Snail cam adjustment might work too. A snail seems appropriate in conjunction with a worm.

Wednesday: My attempts to drill and screw the front plate of the mounting's support fork to the tines were thwarted by non-compatibility between my M5 0.8 taps and the same sized screws. The taps are clearly marked but would not fit any of my M5 nuts. The pitch looks correct when the screws and taps are held up to the light together. The screws match the nuts but the taps are too large in diameter! Without fixing screws the 10mm thick front plate slides upwards when I try to increase polar altitude with the turnbuckle. There isn't room for 6mm screws. Grr?

Thursday: Ordered a cheap set of taps and dies online. They should be okay for cutting threads in aluminium. My own hotch-potch collection of taps and dies were picked up over many years at flea markets.

I bought a [supposed] quality 'Dormer' tap on eBay and it snapped while cutting a thread in an aluminium casting. First time ever in decades of threading aluminium, brass and steel. I could have bought a set of three, no-name taps online but decided against it. No doubt they are all made in China these days . The vendors are just trying their luck in pricing to see what the market will bear.

The new M5 0.8 tap proved to be very hard work. Not so much cutting as rolling the thread! I followed up with my original tap and it cut cleanly to full depth. I now have four screws holding the front plate between the massive PA support, fork blades. I counter-bored the holes for sinking the socket head screws flush with the surface.

Click on any image for an enlargement.

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