On Mon, Jul 19, 2021 at 02:19 PM, alan137 wrote:
Both our methods (laser or allen wrench)? use TVC to remove all the gear backlash BEFORE it gets to the worm.? There is additional backlash between the worm and ring gear (including ring gear eccentricity), and this is the part that varies due to all those factors mentioned.
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Allen,
I have to quibble with you here. TVC does not just remove the gear backlash (I assume you mean gearbox), it removes all the backlash including the worm "mesh" backlash. Did I understand correctly what you said?
For others reading this thread, ring gear eccentricity is a valid point. I hand rotated my ring gear 360 degrees by hand winding the worm and found one small spot where I felt I had a different level of rotational resistance. I made sure this area was not within the operating area of the Dec axis. Previous to my open worm setup, I could? feel high/low pressure situation for each worm rotation. This I took as periodic-error/alignment problem. When I strapped the 1/4" aluminum bar between the bearing blocks it went away. Now this is the old worm design and the OPW does not suffer from this problem as far as I can tell. Also, if you have the old worm you may have the bearing blocks that are silver underneath. These are a different specification the the new blocks. Specifically, the round insert portion on the left hand block is under 3/8" and wobbles in the hole. This is obviously going to lead to big problems. Further, the new block are a little larger and do not fir into the old cover plate, hence why I had no choice in going to an open worm design, which prove fortuitous as I learned a lot from having access to the entire assembly while in operation.
Peter
