What I thought was an easy question is more elusive than I suspected. I have a number of potentiometers that have smooth (not knurled) shafts with a slot cut into the end...it looks like a flathead screw.

similar to this, from Mouser's site

I need a knob for it, but can't find one. I suspect I don't know the right thing to ask for. When I google "knob slotted potentiometer" or similar, I get a ton of pots drowning out anything I might hit for noise, and no useful links if I search for "slotted knob" "knob for slotted" etc.

While a set screw would likely work I'd prefer to get something that's made for the shaft I'm working with. Does someone know what I'm looking for and what search terms I need to use to effectively filter out the pots from the knobs?

  • \$\begingroup\$ Do you know the manufacturer and PN of the pot? \$\endgroup\$
    – The Photon
    Dec 23, 2012 at 17:09
  • \$\begingroup\$ It was a grab-bag box-o'-pots I bought at a garage sale. There's an assortment of pots from various manufacturers, a lot of BI Technologies & Alpha, other unmarked/unidentifiable. However, they all have smooth 1/4" shafts with slots ~2-3mm deep. \$\endgroup\$
    – dwwilson66
    Dec 23, 2012 at 17:12
  • \$\begingroup\$ A large amount of knobs fit that kind of pot. It's fairly standard. \$\endgroup\$ Dec 23, 2012 at 18:04

1 Answer 1


The slot is for adjustment with a flat-headed screwdriver (instead of a knob), and is not generally intended as a feature for the knob to engage with. Just use the same type of knob that you'd use with a purely cylindrical shaft - a knob with a setscrew:

enter image description here

  • \$\begingroup\$ Well then. That's a great reason I wouldn't be able to find a specific pot for this shaft. Set screws it is! Thanks. \$\endgroup\$
    – dwwilson66
    Dec 23, 2012 at 18:07

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