Yup, Dave, I installed a new main shaft after this most recent indoor crash just to see if the hub was wobbling or if it was the shaft, and I had the same No-lift-off thing that I've seen talked about before, and it was obvious that the collective pitch was at least a degree lower than with the other shaft. So I adjusted the servo links to make sure that was the only problem (it was), then I ripped everything apart and dug out all the old shafts for comparison and started measuring. Looks to me like there might be two batches, some of the machining details are different btween the batches, and the hole height varies slightly. The distance from the hole to the _top_ of the shaft is very consistent but this one doesn't matter as far as the adjustment goes.
Not a problem really--just another reason to get a pitch gauge if you don't have one.
Now I'm talking about adjusting the servo links; properly speaking the pitch control links are the little ones from the flybar control frame to the Bell-Hiller mixers, right? These will normally need adjusting, I think, when you change or repair blades, or when you make fine-tuning adjustments to the pitch curve or need to adjust the pitch of an individual blade for some reason.
I think.
I'm trying to figure out if wear will make you need to adjust these links. You've had yours a lot longer than I've had mine. Let me leave a note for the gremlins, maybe they will come up with something overnight.
--John/Jellyson

AlexK, it's a Heli-Rex TMax 420...