Milling tolerance for recessed knob

[fragletrollet]

I want to mill away some frontpanel material so my knobs are slightly recessed (is that the right word?) into the frontpanel. How much bigger should the milled circle be than the knob (skirt) diameter, for the knob to be as flush as possible, but not be obstructed when turned? I'm using fpd.

 

[Dylan W]

I imagine 1 mm clearance around the knob would be enough, so you can make the routed circle diameter 2 mm larger than the skirt diameter.

 

[fragletrollet]

Thanks, I was hoping that would be enough.

 

[Dylan W]

Though on second thought, that requires that your pots/rotary switches are perfectly centered. So you would need to make the shaft drill hole very close to the nominal amount so there's less play, or otherwise have a method to center your pots. If there are multiple pots mounted on a PCB, as in many of the DIY projects here, you have to be very precise with spacings (PCB vs front panel) or the error will add up and some of the knobs won't seat in the milling.

 

[fragletrollet]

The switches will be mounted to the panel directly, no PCB involved. I'll make sure to keep the shaft cutout close to the shaft diameter. What is the norm here? A mm bigger than the shaft diameter? I think they're 6mm.

 

[ruffrecords]

The switches will be mounted to the panel directly, no PCB involved. I'll make sure to keep the shaft cutout close to the shaft diameter. What is the norm here? A mm bigger than the shaft diameter? I think they're 6mm.

The switch datasheet should tell you this.

Cheers

Ian