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I'm shopping for some bulk male header pins and noticed a lot of options for the contact length column. I know 1" is a longer pin than I'm used to and 0.1" is too short, but is there a standard length for these parts, or a fairly standard range of lengths?

I guess for many applications, it's not gonna matter, but when I'm buying a lot of them, they'd better be the right length!

EDIT: breadboards are the main target for these headers.

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  • \$\begingroup\$ What will the pins be mating with? \$\endgroup\$ – Nick Alexeev Aug 4 '13 at 2:24
  • \$\begingroup\$ Breadboards, and standard female headers, mostly. (female headers don't seem to specify a contact length) \$\endgroup\$ – tummychow Aug 4 '13 at 4:49
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    \$\begingroup\$ The great thing about standards is there are so many to choose from! \$\endgroup\$ – user3624 Aug 4 '13 at 5:00
  • \$\begingroup\$ @tummychow you'd be surprised about the variations in female header variation \$\endgroup\$ – Passerby Aug 4 '13 at 5:23
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""Standard"" length means any length that fits your desired use, unless you are talking about using them with some specific goal in mind.

A through hole header has five main dimensions. Pitch between pins, size of the pin, length of the bottom side, length of the post, and length of the top side.

enter image description here

The most common are 0.1" pitch, 0.025" square pins. "A" in that picture is the side that goes through your pcb. If your pcb is very thick, and A is too short, you will not be able to properly solder it. If the pcb is too thin and A is too long, you could short something out, have a lopsided board or have to cut them. "C" in that picture is the top side length. This mates with a connector. Too short and it might not be secure or might not have a good electrical connection. Too long, and the connector doesn't sit flush with the posts, so you might end up bending them.

Having just measured a ide/pata header, it is ~0.25" C with a B total length of ~0.435" (7/14th) (eyeballed/rounded). For samtec parts, this is actually A = 0.100", C = 0.230", B = 0.430". This is the general IDE/PATA standard header, and pretty much all computer headers fit this.

Personally I find those too small for breadboard or general use, longer headers are more useful (I go with slightly longer .126/.456/.230 or headers that are pretty much end up equal length on both sides of a pcb .300/.630/.230)

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  • \$\begingroup\$ Yeah, I'm mostly looking for breadboard-compatible headers. I'm guessing the order of those dimensions is A/B/C? It seems the digikey "contact length" column is referring to C but I'll check the drawings to be sure. And by "too small for general use", you were referring to A=0.1"? \$\endgroup\$ – tummychow Aug 4 '13 at 3:09
  • \$\begingroup\$ @tummychow yes. The 0.1" bottom length is a bit too short for a breadboard, makes it too easy to pop out. C is normally contact length, as c is the one that mates with another connector. \$\endgroup\$ – Passerby Aug 4 '13 at 3:16
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The ones I'm holding in my hand are about 6mm. That should work for anything but the most recessed sockets.

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