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Monday 9th. 47F. Grey and mild. I had another idea about spring loading
the RA worm. The hinge could be the spring itself. A leaf spring. First
find your spring material. Bronze? Hammered brass or copper? I have some
bronze strip somewhere. Found it. Only 50mm or 2" wide.Having removed and dismantled the RA worm housing, pulleys and motor I decided against leaf springs. I have the ability to adjust the RA wormwheel up and down the PA shaft. So there was room for a length of 60mm angle profile aluminium to beef up the motor housing. Springs could be inserted between the two.
I
discovered backlash in the Beacon Hill worm. Tightening the single grub
screws, which clamp the bearings, merely locks up the bearing races. So I'm looking at stopping
end play, more directly, with thin washers or shims on the outer race .The sky seems to be brightening. So I should make a decision about springs to get the mounting back to active duty as quickly as possible. The short sunny periods never extended into anything useful.
I rebuilt the motor and worm housings using reversed screws [for easier access] and a lighter tension spring. I also added two more brass weights to the saddle to improve the balance. The previous motor stalling seems to have been cured. I have new IKEA towel rails, in stainless steel, to provide sliding weight rails to actively optimise the balance. They need taller standoff feet or serious packing for their bases.Or they could go inside the channel section saddle.
The further a balance weight is placed from the pivot, or axis, the more useful it becomes. A weight near the axis has hardly any change in its moment. [Mass x Distance from the pivot.] Sliding weights are much more useful at a distance from the axis because they help to balance a "nose heavy" OTA far more effectively. Removing components from the OTA often demands a balance weight to compensate. This is where the sliding weight scores most heavily.
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