I need to lock a soldering breadboard to a 75 mm coupler cap. The picture below is upside down: the board will be hanging underneath the coupler cover.


And the assembled pic:


The board is inserted into the coupler after I put one of the caps on (the upper one in particular, upside down):

enter image description here

That's why I cannot fix the board tightly right away to the cap due to my mounting constraints (everything is packed in a sealed 75mm coupler). So after I assemble the board with my sensors, I need to lock (and unlock on demounting) the board to the upper cap.

I thought of spring clips/clamps

spring clips/clamps

but I'm looking for something that locks the 1.5mm wide board upon insertion. Some spring mechanism that locks the board vertically when force is applied. I cannot google them. Any ideas?

The board weight is 90 g.


Had jsotola written down his answer to use magnetic clips that attach to a piece of metal under the cover cap, I'd have marked it as the answer.

But in time I discovered a simpler approach that works just in my case. I noticed that I could add a small bump on both sides of the solder board to make friction enough to hold an 80 g board when sliding in the coupler cap. Since I pcb-print the boards, adding a small bump won't be a problem. And non-printed boards can be wrapped in a few layers of duct tape to expand the width a little bit to fit tightly into the coupler.

  • $\begingroup$ If you use the spring clips/clamps on the receiving end, is there any room to also restrain the top of the board (say from the sides of the coupler body)? How much room do you think you'll have after the sensors are installed? $\endgroup$
    – user138719
    Mar 12, 2023 at 13:24
  • $\begingroup$ "to restrain the top of the board" - yes, that's what I want. There is definitely room for two or more spring clips of 10x5 mm, attached to the upper cap. Maybe I'll find room for the clips on the coupler sides too. It's just I ain't quite sure that spring clips like I showed (even with no gap), attached either on top or on the sides, will hold the board. $\endgroup$
    – dizcza
    Mar 12, 2023 at 15:36
  • $\begingroup$ use magnets ... $\endgroup$
    – jsotola
    Mar 12, 2023 at 19:12
  • $\begingroup$ @jsotola a good idea, thanks. Do you have something particular in mind? Googling "magnetic clips" shows a lot of garbage... $\endgroup$
    – dizcza
    Mar 12, 2023 at 21:41
  • 1
    $\begingroup$ amazon.com/Uxcell-a15080400ux0550-Vertical-Circuit-Holder/dp/… $\endgroup$
    – Phil Sweet
    Apr 9, 2023 at 0:49

1 Answer 1


Glue, or drill seal and glue some of those through nuts and fit brackets to your board.

Two small screws through the brackets into the nuts will suffice.

  • $\begingroup$ Any solution that requires screws and nuts to mount the breadboard won't work: the mounting process happens after I assemble the coupler with one of the caps. I've updated the question. So I cannot screw the board to the cap. Or I misunderstood your answer? $\endgroup$
    – dizcza
    Mar 12, 2023 at 9:48
  • $\begingroup$ Needless to say, I need to be able to disassemble the coupler at any moment. $\endgroup$
    – dizcza
    Mar 12, 2023 at 9:50
  • $\begingroup$ Why does my answer mean your coupler cannot be disassembled? Given that the board fits inside the cap and the cap fits inside the coupler body then disassembly is not an issue. $\endgroup$
    – Solar Mike
    Mar 12, 2023 at 9:59
  • $\begingroup$ Have I understood you correctly that you suggest mounting brackets like this one side to the breadboard and another to the cap? As I said, I won't be able to tighten the board to the cap right away. I first need to insert the board into the open coupler and only then put the caps on. It is still possible to (1) put on the upper cap to the coupler and then (2) tighten the board to the upper cap with brackets as you suggest but it's inconvenient. Are there no easier ways? $\endgroup$
    – dizcza
    Mar 12, 2023 at 11:37
  • $\begingroup$ And with the sensors taking up almost entire space in the coupler it would be hardly possible to tighten the brackets with a screwdriver... from either side. $\endgroup$
    – dizcza
    Mar 12, 2023 at 11:40

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