Thanks for posting that and clearing it up, sort of ...

The ratios I had heard of in the past were the std 7% overdrive, 7% under ... and ... 1:1, not the 5.5% overdrive - that is big news to me!

I wonder if 14:14 or 15:15 could be shimmed together to make 1:1?

(although I would advise against it because of increased wear)

Now that this has come to light, I am surprised that more ratios were not made. While Oxley & Kies were working for McCulloch, they made ratios in steps from 2:1 reduction to 1:1 to 1:2 overdrive.

I would say that the 7% reduction gears would be the most desirable today; they would make the motors a lot easier to find props for.