Hi Seb,
As I have said many times the gen I OPWs were a much better design from the purely mechanical perspective. But they were expensive because the took many small pieces and a lot of time to make and assemble. The performance differences are very small and most likely not reliably measurable. The Oldham is designed to allow for a small misalignment between axes that are parallel. The issue here is that there are slight velocity changes produced by the shaft misalignments not being parallel and varies depending on the angle of the axles. In this case the difference is very small so it works ok.?
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Unfortunately the gen I OPWs are long out of production and nobody has stock of them any more AFAIK anyway. Anybody who know the differences is not likely to sell them as they are the best version with the most potential to produce extremely low PE.
So with your gen II OPW you can simply pull the black plastic T-cap off or replace it with the same size cap screw. That T-adjuster is used to lift the worm from the worm wheel and limits the worm's inward travel on the current gen II OPWs when used with the spring stack used in the current version mounts. I'm pretty sure the hardware is available off the shelf from Losmandy or you can turn them on a lathe from 1" aluminum rod stock and supply your own springs.? ?
With either the gen I OPW or gen II OPWs you can spring load the OPW by drilling and tapping a small hole in the base or deck plate where the empty hole in the gen II OPW is and run a small cap screw through the hole in the OPW. I am telling you this assuming you know that if you screw this up you are on your own. To drill and tap the hole is trivial but requires a quality machine shop with a mill and skilled operator. You will damage the existing hole in the deck plate for the OPW if you drill too deep, there is no reason to drill through so make sure you do not. Also don't do this at home!??
Anyway you can then put machined spring seats on both ends of a small stack of Belleville discs and use the cap screw length or shims to limit outward travel of the OPW. The springs only need to allow the OPW to move in and out maybe 0.002" total run out while keeping the worm fully engaged in the worm wheel and to minimize bouncing from face to face between the worm and worm wheel surfaces. This is a very small range of motion and obviously the block surfaces and the OPW retaining screw seats need some slick but thin lubricant and the inner mounting post needs to be loosened slightly, just enough so the gen I OPW can rotate and the outer mounting post needs to be set about the same and both need a mild thread adhesive to retain the fasteners and prevent excessive movement. The OPW only moves a very small amount depending on the concentricity of the bearings and worms gears you have.??
Good luck!
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Chip Louie Chief Daydreamer Imagination Hardware?
? ?Astropheric Weather Forecast - South Pasadena, CA?
Chip Louie