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I am looking for the name of the component in this picture:enter image description here

Does anyone know off the top of their heads?

I'm working on designing a product that requires 2-56 threaded holes in a PCB, and I need it to be as flush to the surface of the board as possible due to physical size constraints. The component in the photo looks like it inserts into the through hole and solders in place--that's exactly what I need, I just can't figure out what it is called so I can order some.

Thank you in advance for the help! Eric

EDIT: A user on another forum pointed me to the original site for the image: http://www.robotroom.com/Yummy-Robot-4.html

They say: "The mounting holes in the PCB were sized to accept threads (0.067-inch hole for 2-56 screws). I’ve been threading holes in PCBs for many years. I assumed that the plating on the interior of the hole would be the material that would get threaded. However, now that I get a close look, I can see that the through-hole plating is lost in the process, and that the threads are made in the garolite substrate. I suspect that the threads in the substrate will have a much more limited life span of having the fastener installed and removed."

So it looks like this indeed just a hole with threads cut by the screw as it's installed. Thanks for all the help, everyone!

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    \$\begingroup\$ Google "pcb threaded insert" is returning many results. Look at the images it is returning for the idea. \$\endgroup\$
    – Eugene Sh.
    Commented Jan 12, 2017 at 16:37
  • \$\begingroup\$ Thanks, Eugene! I did google "pcb threaded insert" prior to posting (that's how I found this image) but none of them seemed to be as flush as this one. I was hoping it had a specific name that would make a supplier easier to track down. \$\endgroup\$
    – user135750
    Commented Jan 12, 2017 at 17:00
  • \$\begingroup\$ You mean, they are all not as flush as this one is ON THIS SIDE. Maybe look at the back of the picture? If this in fact is a threaded insert, rather than a twonk claiming it is after threading in a screw in some solder, which it very much looks like, how do you know that the other side is flush? Hint: It isn't. \$\endgroup\$
    – Asmyldof
    Commented Jan 12, 2017 at 17:22
  • \$\begingroup\$ Can you disclose why you need a threaded insert just like that? Is that for board-to-board interconnect? Maybe there are alternative solutions to your real problem that involve a different approach. \$\endgroup\$
    – LorenzoDonati4Ukraine-OnStrike
    Commented Jan 12, 2017 at 21:09

4 Answers 4

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They are called PCB threaded inserts: http://www.mac8usa.com/threaded-insert-TH-lev2.php
They are pre tapped and can be surface mounted with other components. The PCB is rarely ever tapped since the board layers may separate and the threads are mechanically weak.
Earlier variants of threaded inserts had a longer rear tube which was spin or pressure pressed over so forming a complete enclosure for the PCB edge. Very small inserts can be pressed into plated through holes, though these seem to get little use these days.

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  • \$\begingroup\$ Thank you, Jack! These look perfect. They only have a .011" lip, which should be ideal for my application. \$\endgroup\$
    – user135750
    Commented Jan 12, 2017 at 17:29
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I don't think that's a component

If you look closely, the metal layers are only on the top and bottom of the PCB. The threads themselves are cut into the green material of the PCB. The metallic bits are just circular pads on the top and bottom of the board, which will help prevent the board coming apart as it is tapped. The way to make one of these is to put a circular pad on both sides, with a hole in the middle slightly smaller then the standard pilot drill, then drill and tap as you would any other material. The end result will not be very strong.

They do exist though

As Eugene points out in his comment, the search term "PCB threaded insert" should get you some relevant results. These inserts will be much stronger then just drilling and tapping. They come in different types, some screw in like a wood screw, some press in like T-nut, there may also be solderable ones, but I've never seen one.

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  • \$\begingroup\$ If it's mounted on the PCB how could it not be a component?? \$\endgroup\$
    – Jack Creasey
    Commented Jan 12, 2017 at 16:58
  • \$\begingroup\$ Thank you for the quick response! I had no idea that tapping PCBs was an option--that's a really interesting observation. For what I'm doing, I don't necessarily need the strength, that might be a viable option. I did google "pcb threaded insert" prior to posting (that's how I found this image) but none of them seemed to be as flush as this one. I was hoping it had a specific name that would make a supplier easier to track down. \$\endgroup\$
    – user135750
    Commented Jan 12, 2017 at 16:59
  • \$\begingroup\$ @JackCreasey It's not mounted on the PCB, it's made out of the PCB. The silver metal part is just solder - either the PCB's HASL finish or more likely built up slightly with some extra solder. You can even see some copper around the rim of the hole where the tap has cut it. And inside the hole the threads have the green-white colour of FR4 which has been cut but not cleaned. \$\endgroup\$
    – Jack B
    Commented Jan 12, 2017 at 17:41
  • \$\begingroup\$ @Eric Some would argue that tapping a PCB isn't really an option. FR4 really isn't designed for machining, and the threads will be very weak. They may even come out with the tap. Look for a suitable threaded insert if you can. \$\endgroup\$
    – Jack B
    Commented Jan 12, 2017 at 17:47
  • \$\begingroup\$ @JackB. You right that that photo is a tapped hole in PCB with just a solder ring front....but completely unusable as a mount point. The FR4 will NOT sustain threads like this in any stress situation. I have seen thick FR4 (0.25" or more) get tapped, but always with a thread insert to take the load. The correct way to do it is to use thread inserts. \$\endgroup\$
    – Jack Creasey
    Commented Jan 12, 2017 at 18:26
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Looks like M2.5 "Zero" Height SMT Threaded Insert P/N 24929 by Keystone https://www.mouser.co.il/ProductDetail/Keystone-Electronics/24929?qs=Znm5pLBrcAJPd1Bwfdw1vA%3D%3D

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Keystone has a series of "zero-profile" inserts. p/n 4929 for 2-56 thread, 4939 for 4-40 thread. No metric options. Stickup on top side of PCB is only 0.012"/0.30mm. Available at Digikey.

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