I'm trying to crimp some pins onto 20 AWG wire.

I can either use a tool like this:

specialty crimper

Or I can just use pliers, which are obviously cheaper and more readily available. Why should I use the more expensive tool?

  • $\begingroup$ The whole idea of crimping is to create an gas-tight connection with very low resistance. Crimping with normal pliers will probably not make a sufficient contact that will oxidize or corrode over time. Eventually, as the resistance increases, the connection will overheat from the ciurrent and could cause a fire. $\endgroup$
    – DoxyLover
    Commented Aug 13, 2015 at 18:31

2 Answers 2


It's all about the amount surface area in contact between the two materials.

A pair of pliers will create points of contact on two sides of the wire.

The specialty crimper you linked will provide contact on four sides of the wire.

Having four points of contact provides:

  • Better electrical conductance between the pins and the wires
  • Better mechanical resistance (aka a friction fit) to pulling and the pins are more likely to stay attached.

The proper crimper will indent the cylindrical body of the contact, leaving the outside diameter unchanged.

Pliers will simply squash the contact, making it oval, and larger than the original diameter in one direction. This may prevent the contact from seating correctly (or at all) in the connector housing. The distorted contact will probably make it impossible to use the contact removal tool to remove the contact from the connector.

  • $\begingroup$ Do you mean that the outside diameter will not be increased with a crimper? Because it should not stay the same if it is compressed. Just a nit pick. $\endgroup$
    – hazzey
    Commented Aug 14, 2015 at 0:52
  • 2
    $\begingroup$ Peter, you really need to combine your accounts... $\endgroup$
    – hazzey
    Commented Aug 14, 2015 at 0:59
  • $\begingroup$ @hazzey: the proper crimper will make four small indents in the body of the contact - the outside diameter of the contact should not be changed (perhaps I should add "much"). Ordinary pliers will mush the contact, makeing a rough oval, with one dimension being much smaller than the original, and the other dimension being larger. $\endgroup$ Commented Aug 14, 2015 at 6:40

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