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I recently received my largest batch yet of assembled PCBs. The design hasn't changed since the last order, but the supplier's stock of a socket I had been using has been depleted, so I substituted a different socket.

Old socket

old socket

New socket

new socket

I've got some headers from various suppliers, such as this, this, and the ones that come with the part intended for this socket, none of which will fit into the new socket. I've tried taking a single pin and forcing it in with a pair of pliers, but the pin just bent.

Sullins headers

Sullins headers

Tayda headers

Tayda headers

Adafruit headers

Adafruit headers

Production of my product is stalled until I can resolve this, and I live in Aotearoa New Zealand, which is about a week minimum from any supplier. So in desperation, I'm wondering whether it would be OK to sand down the header pins to make them fit. I realise this will remove the surface coating, and that's why I'm unsure if this is a good idea.

The product is a guitar effects pedal, and it's meant to last a long time. I've been careful not to mate gold pins with tin sockets in the past (because this might create a kind of cell, causing corrosion), so I'm aware sanding is pretty dodgy.

I've also tried taking some other sockets I have and using them as an intermediary, but the legs of this socket are so thin they don't make a good contact with the socket on the PCB.

Piggyback socket

piggyback socket

Any other suggestions?

Would I be justified complaining to the PCB supplier that the socket they supplied is defective, given that it won't accept any of the pins I have tried? I mean, headers are headers, right? They are supposed to be a fairly standard fit, aren't they?

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    \$\begingroup\$ Why exactly is it essential for your product to jam header strips into IC sockets? Doing that for production purposes is just plain fishy. \$\endgroup\$
    – Lundin
    Jan 5 at 7:27
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    \$\begingroup\$ @Lundin don't know, modularity is not a sin - quite the opposite in terms of in-field service and upgrade paths. At the size of these daughterboard, the holding force of especially the high-quality machine pins will suffice for any non-aerospace application, I'd guess - 70 g × 28 pins=1960 g (times earth acceleration) holding force for boards that weigh in the order of 10 g, that leaves a lot of room for rough handling of the encased product. \$\endgroup\$ Jan 5 at 11:43
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    \$\begingroup\$ @ConstantineA.B. "modularity is not a sin" Nobody said it was, but using the wrong connectors and mechanics for whatever they are trying to achieve here might be a sin. From what I've caught up from a professional guitarist I know, guitars mainly use through-hole components for ease of maintenance indeed - nothing wrong with that as such. \$\endgroup\$
    – Lundin
    Jan 5 at 11:52
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    \$\begingroup\$ Unless you exactly specified the type of IC socket to be used and your manufacturer substituted different ones without your approval, I dont think you have any grounds for complaint to the manufacturer. You're using those IC sockets "off-label" as board-to-board connectors. The substitute ones are arguably better quality when used for their intended purpose, but sadly don't work for the "off-label" way you want to use them. \$\endgroup\$
    – brhans
    Jan 5 at 12:22
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    \$\begingroup\$ If you made the substitution, complaining to the manufacturer would be like complaining your US plug wall does not plug into a UK outlet. Machine pin sockets were never made to fit square headers. This is not a manufacturing error. Technically, even if they made the substitution you might not have a leg to stand on given the non-standard usage. Who made the substitution? You swap between you and the PCB supplier, \$\endgroup\$
    – DKNguyen
    Jan 5 at 16:01

3 Answers 3

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As you can (sadly) see, nope, sockets are not sockets!

You got precision pin sockets, do you need what is usually sold as precision turned pin headers, or precision machined pins. These are cylinders, instead of prisms.

These are all candidates, but check the individual dimensions of the pins against your socket's data sheet! (The data sheet isn't great, but does mention pins of nominally a diameter of 0.432 mm, as far as I dare interpret it)

https://www.digikey.com.au/short/3j1mdh3n

And: forget about sanding. Not going to realistically be possible.

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    \$\begingroup\$ The Mill-Max 350-10-164-00-001000 is one possibility. I've used them before. \$\endgroup\$
    – Dave Tweed
    Jan 5 at 4:07
  • \$\begingroup\$ Mill-Max 800 series may possibly work. \$\endgroup\$
    – qrk
    Jan 5 at 4:43
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You substituted a higher quality construction (screw machine pins) of IC socket for a cheaper kind of (stamped pins) side-wipe IC socket.

They are IC sockets and neither type is intended to fit a 0.025" square header pin, but you can often force it into the latter. The former, not so much.

You can purchase single-row female connectors that are intended to accept a 0.025" pin, and are gold-plated if you so desire. Here is one at random, but there are many suppliers.

enter image description here

Since you appear to have the sockets already soldered in, there are thinner round-pin headers, but they tend to be a bit pricey, from Western sources, anyway.

enter image description here

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  • \$\begingroup\$ I find that it's rather common to use blade-style pin header on PCBs that are meant to be used as kind of DIP ICs, minus the I... \$\endgroup\$ Jan 5 at 3:59
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    \$\begingroup\$ @ConstantineA.B. What's an example of 'blade-style' pin header? I don't think I've noted that kind, only square and round in 0.1" pitch. \$\endgroup\$ Jan 5 at 4:02
  • \$\begingroup\$ Can look this up, but just as DIP IC lead frame, stamped from a thinner sheet of metal \$\endgroup\$ Jan 5 at 4:04
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The one thing that might fit is an IDC-to-DIL transition connector, which typically has thin but robust pins similar in dimension to a standard chip.

I have on occasion used that sort of thing when I've needed to make a breakout, e.g. for a logic analyzer.

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