Printed Circuit Boards — MIL-TFP41


It smell something… sniff sniff … yes, I smell BS!

Initially I was pretty happy when these boards finally arrived. They looked reasonable, nothing was raising my suspicion – BIG mistake.


Now the Chinese New Year is upon us once again. No chance to get a quick fix I suppose. Oh well…

Let’s play a little game. It is called “Will it fit?”


The piece of wire is exactly 0.80mm thick. The finished diameter of the holes should be 0.80mm as well. Who would have guessed, right?


As you can see for yourselves, it doesn’t quite fit.


Same BS viewed from the other side. The pin width of this microMaTch connector is 0.60mm [verified], so it should go in.


Something is obviously wrong. I did think about the HASL process, which is a bit notorious for leaving too much solder behind, but that wasn’t the main issue here. I managed to insert a drill into one of the holes. The drill is exactly 0.58mm wide. It was a very close fit.


I ran a 0.72mm drill through 4 of these holes to see if this was a viable option. One hole still seems to have some copper left, but the remaining three were destroyed in the process – sigh.

So what happened in the factory? Under-sized drills, excessive copper plating… who knows. One thing I know for sure is that IT SUCKS!

Oh, just in case, the gerber files are OK.


I don’t see any fault on my side. Let’s see if I can get replacements boards.

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4 Responses to Printed Circuit Boards — MIL-TFP41

  1. David Hathaway says:

    You may already know this but have you thought about using seeedstudio for your pcb’s?

    They offer a reasonable service for a few dollars. Here in the UK I only use local PCB manufacturers that I trust and have used before, so I know what to expect when they arrive.

    I have nearly all of my boards supplied in HASL and I have never had a situation where it has caused the plated through holes to become smaller than I have specified.

    I hope you get that sorted, they should re-supply decent quality boards free of charge. Good luck, David.

    • robert says:

      I’ve used SeeedStudio before, and many other Chinese front ends for PCB factories. I tend to apply a round-robin principle with my PCB orders.

      My suspicion towards HASL was a red herring. The holes are clearly too small, even after sucking all solder away.

      Using local board houses is prohibitively expensive for hobby stuff.

  2. David says:

    Yeah, the fabrication is bad – likely nothing to do with the HASL. Tell us who took your money to do this board.

    • robert says:

      I had these boards made at “Elecrow”, not the first time I used them btw. No issues until this one.

      I got in touch with them and the boards were re-made without any issues this time – at no cost to me of course. They claimed a drill-bit broke and was replaced with an under-sized one – or that is what the factory told them.

      A bit unfortunate and time-consuming, but it was handled alright.

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