I've finished my 767 quadrant and am generally very happy with the build.
One problem that has started developing is a tendency for the potentiometers to slip relative to the stem axis, if the friction brake is set tightly. In any case I believe a more positive way of preventing this slippage is necessary, especially considering wear in the long term. I believe it is not sufficient to rely only on "tightness of fit" or friction between the pot shaft and the walls of the hole in which it sits in order to prevent this.
Today I downloaded your 737v3.3 Quadrant files (Order 12538) and noticed that you have provided a hole for a grub screw within the stem to secure it's connection to the potentiometer shaft more positively.
I request you to modify the design of the speed-brake and throttle stems of the 757/767 quadrant, to similarly allow for the insertion of a grub screw.
Thanks for your attention.