Searching for 77-20996
Thanks for writing. It seems other customers who inquired about a similar part were directed to our 39-205 fold down crank handle as a possible replacement. Have a look. This has a spline size of 11/32". Could this work for you? Get back to us and let us know.
I'm afraid this is not a measurement we can determine from just a tape measure held up to the spline. Your tape measure doesn't appear to have the 1/32" range on it, either, so this isn't really something we can eyeball.
You need to measure your hardware as carefully as you can and use your best judgement. I'm afraid there isn't a photo you can take that will allow us to confirm this information.
You want to measure the overall diameter, including the teeth.