Paulie: If you don't mind my input here, the bias control is a fine tune adjustment that works similarly to the regulator adjustment. With the newer machines I don't find myself using it as much any more. In fact I rarely use it now. But what you do is adjust the regulator so that as soon as you depress the foot pedal you get a nice, crisp tapping of the handpiece piston without any vibration or flutter. You can then use the bias control (if desired) to fine-tune to get on that perfect threshold.
Thanks a lot for your fast support, Sam! I'll keep your advice in mind and try it like you said
first tune the GraverMax (air pressure & speed) before fine tuning with the bias control. Kind greetings, Paulie
