Problem with pots

[ericlen838]

First time building an amp and I can't get the alpha pots to mount straight in my chassis.  The push pull pots don't have a tab on them and they mount perfectly.  Do I need an extra nut to put on the inside of the chassis.

[PRR]

The right thing to do is drill a 1/8" hole where that lug hits. Now the pot can't turn even when the nut gets a little loose.

Many folks just snip-off the lug.

[Searing]

I always broke off the tabs, but now wish that I was more particular and drilled the holes.  Just for that feeling of correct completeness.

Chris

[HotBluePlates]

... wish that I was more particular and drilled the holes. ...

There's a trick to help do that (I've only drilled the holes a couple times):

Assuming the hole for the mounting bushing is not over-sized, pot the pot in it but with the body of the pot on the outside of the amp. If you want the solder lugs to face up, have them down when outside the amp. Push the pot in place, until the mounting tab contacts the chassis, and twist it back & forth a few times.

When you remove the pot, you should have a faint arc where the tab was scraping against the chassis. Center your bit on that arc and drill your pilot and final holes.

Now when you install the pot from the inside (lugs up now), the hole for the "anti-rotational tab" will be right where you need it. Don't worry if it's not perfectly horizontal; you'll adjust the knob to point wherever it needs to when you have your faceplate on.

[stratele52]

Tab is not useful if you use teeth washer inside side of the face plate.