I want to attach a panel mount potentiometer to a PCB. But I need the bushing to be grounded. Ideally I would just make the hole for the pot thru plated but the fab does not permit really large thru plated holes. So my first attempt is two SMD pads with a thru plated hole in the middle like this:

eagle bushing contact

This obviously has issues. Can anyone recommend an alternative solution?

If not, do you think this would work if I accept all of the overlap and clearance issues with these pads? Will the hole actually be through plated so that the top and bottom pads are in fact connected?


As suggested by Peter Bennett, a possible solution is to make a circle using the bStop layer to expose the ground plane:

eagle bStop for bushing contact

So there would be no contact on top but I think because the tin is slightly raised and soft it should make good contact with the bushing. We'll see ...

  • \$\begingroup\$ Is that a via or a through-hole pad? If the latter, try adding it as a via in the layout rather than a hole in the footprint. Also, refer to this question for connecting the pads. \$\endgroup\$ Aug 18, 2016 at 5:01
  • \$\begingroup\$ Thanks. Append does help a lot with the schematic. But I have to manually create two vias (one from bottom to top and one from top to bottom) to resolve all routing and DRC errors. I would be fabulous if there were a more streamlined solution. \$\endgroup\$
    – squarewav
    Aug 18, 2016 at 5:43
  • \$\begingroup\$ It looks like you have a ground plane around the hole, so just creating a larger "hole" in the solder mask should allow a good connection between the pot bushing and ground. No need for an explicit pad or via. \$\endgroup\$ Aug 18, 2016 at 16:25
  • \$\begingroup\$ Mmmn, that is kind of brilliant. How do I create a hole in the solder mask. What layer means "don't put solder mask here"? \$\endgroup\$
    – squarewav
    Aug 19, 2016 at 0:03

1 Answer 1


I doubt that the potentiometer's nut will make a reliable contact with the small pad like that. To make a reliable contact, I would make the pad encircle the hole completely, and put a star washer between the pad and the nut. Alternatively, do that on the bottom layer.

  • 1
    \$\begingroup\$ The pads encompass more than 45 degrees and the pads are on both sides so at least one tooth of the washer should make contact. But I agree it is not ideal. If there is a way to make a circular "pad" with a hole in it, I'm v. interested. \$\endgroup\$
    – squarewav
    Aug 18, 2016 at 5:46

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