18.01.2021 Four weeks to get a few drive belts from Conrad Electronics! AVOID!

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Monday 18th light dusting of snow overnight. It started raining at 11.30am.

After waiting for nearly FOUR weeks the longer, mounting drive belts finally arrived today from Conrad Electronics. I shan't bother with them ever again!

Nevertheless, I now have three longer drive belts to play with. My rebuild and heavy reinforcement of the RA drive, motor & worm assembly had pushed the pulley shafts further apart. Making the original belt too short. 

My problem now is making useful progress with air temperatures close to freezing. Handling metal under those circumstances is actually quite painful. Even the thinnest "industrial" gloves are unsuitable for fine assembly of tiny screws. If I bring the assembly indoors everything will be saturated in condensation for hours and I shan't have access to my tools.

I chose to wear Vileda, nitrile, disposable gloves. My nose was dripping but the gloves protected me from the cold metal and did not inhibit fitting small screws. The considerable, new offset of the worm has to be transferred to a new 10mm thick motor plate. I have marked out the new screw holes and will drill them before sawing out the plate itself. 

The new, angular contact bearing, on the pulley end of the worm, will be resisted by the motor plate. I made the hole too large last time. To make room for the ridiculously oversized, timing pulley boss. Which has since been reduced in diameter below that of the bearing OD. 

The new, 260T timing belt fits with the brass idler roller in place. I may turn a slightly larger idler to tighten the belt. It is not slack, but any looseness will result in backlash. Particularly when changing drive direction. No point in going to all this trouble just to ignore a known weakness.

I made progress on the new motor plate. All holes drilled except for the 27mm worm drive, pulley hub clearance. I have had to order a couple of hole saws. My random collection didn't come close. Given the tendency to bore slightly oversized I ordered a 26mm as well. I can practice with both on a scrap of aluminium before deciding which to use. I need to retain the rim of the nearest worm bearing with little room to spare. I may turn down the pulley hub a little more. Diameter isn't critical and I have shorter grub screws if I need them.

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