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Are there probes that are designed to insert snugly into 40-mil holes (about the size of those needed by a DuPont connector)?

I am thinking of something that looks like a banana plug with springs on the side, but is very small so that it is easy to insert into a plated through hole without soldering a header in place, but I am not sure what to search for because I do not know what they are called.

Question:

  • Do small sprung PTH probes exist?
  • What are they called?
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This is the fourth time I have seen this question asked in a forum. In none of these cases has anyone been able to identify such a plug. Yet, I have seen them used in a lab. I looked and looked, and I have never found them for sale. Sorry to say.

In lack of that ideal solution, the next best solutions to connect to pads in a line spaced 2.54 mm I have seen in those forums are:

  • Use a pin header and let the weight of the cable tilt the pins so that they contact the barrels inside the vias. This is good enough for a short test or for programming.
  • Use a pin header and bend every other pin slightly, staggering them, then shove the pin header in the line of pads. The pins with press against the barrels inside the vias due to their elasticity
  • Shove the square terminals for a power connector into the holes, deforming the vias and connecting through interference fit
  • Use a programming clip with test fixture probes

I know these solutions are not ideal, but that's the best workarounds that have been suggested.

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It's more typical to use spring-loaded pins that are conical and engage the plated-through hole at the edge of the hole. They're called pogo pins (more of an informal name), spring probes, test probes etc. From here are some typical shapes of heads.

The 'convex head' would be used with an unpopulated hole, and the concave head on the pin when the connector is populated.

enter image description here

If you look at Tag-Connect cables for inspiration you might be able to come up with something that could be 3D printed or machined to accept standard Pogo pins and make contact with a header footprint- there would need to be some means of retaining it if you don't want a more complete jig/fixture arrangement. If you don't have control over the PCB layout, that's less likely to be possible without a fixture. For EEPROM (re)programming hand-held arrangements are sometimes used, since it only takes seconds, and if it fails verification it can be repeated.

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    \$\begingroup\$ The pogo-pins need a solid surface for the board to rest and a reference holder to push the pin. The question is if there is a practical solution to hold a wire/probe in a test hole so you can move the board freely. And preferably removable and reusable. \$\endgroup\$
    – Ale..chenski
    Commented Feb 20 at 2:04
  • \$\begingroup\$ @Ale..chenski Aside from the rather expensive Tag-connect connector/cables (which have guide pins and snap legs) I don't know of any. Of course it's a lot easier to improvise a fixture now that everybody and his dog has a 3D printer. \$\endgroup\$
    – Spehro Pefhany
    Commented Feb 20 at 10:10
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    \$\begingroup\$ In my experience, "pogo pin" and "spring pin" refer specifically to the types that are spring-loaded; fixed-length probes are never called that. I'm sure you're aware of this, but your answer doesn't mention that detail. \$\endgroup\$
    – Hearth
    Commented Feb 20 at 14:35
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    \$\begingroup\$ @Hearth Thanks, edited. It wouldn't be much of a pogo stick without a spring. \$\endgroup\$
    – Spehro Pefhany
    Commented Feb 20 at 14:47

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