Joe, I would be interested to find out what your issue was. I had an "incident" at a contest last weekend. I am running a 4035-330 on 8s and a 16-8 APC. Tell me if if this sounds like what happened to you.

After landing my last flight on Sunday I noticed that the prop was loose. On getting home and removing the spinner and prop, I found that the aluminum back plate had welded itself to the shaft. I guess that when the prop came loose the prop and spinner started to spin on the shaft. I did seem to notice a momentary loss of power on and up line, but the friction between the spinner backplate caused them to weld themselves together. After this happened the spinner was driving the prop.

Now I had balanced everything, but apparently the screws holding the motor to the X mount had come loose. Motor shaking on the mount is probably what worked the prop nut loose. Like I said, everything was balanced pretty well, so there was not a lot of vibration, but apparently it was enough.

My solution. . . Locktite on all motor mount screws and a jam nut on the prop shaft.

O.K. I just reread your post and you are talking about the True-Turn type adapter. There are two types of 8mm threads commonly used. one has a 1mm pitch, and the other is a 1.25mm pitch. I believe True Turn sells both. Measuring mine with calipers, I get a 1mm pitch