After choosing a Molex connector (C-Grid III 90142 series housing) for my PCB

I ordered the corresponding crimp contacts.

I assumed I would be able to crimp them using my Knippex crimping pliers.

(source: knipex.com)

I've used the knippex plier a lot for standard crimp pins in Dupont housing.

But I'm having some trouble with these C-Grid III series contacts. It seems that Molex has a (very expensive) tool specifically for the C-Grid III Series.

Am I to assume that some contacts can only be crimped by the manufacturers tools ?

I assumed that a universal crimper would be able to crimp anything you throw at it.

Are there standards when it comes to these crimp contacts (so that universal tools can make use of it) ?

  • 3
    \$\begingroup\$ Molex purposefully makes only just not standard stuff to brand-tie you. Which makes me very happy companies like Wurth make compatible types with better retention and lower contact resistance (some more of my major issues with molex connectors) \$\endgroup\$
    – Asmyldof
    Mar 9, 2016 at 23:21
  • \$\begingroup\$ You wouldn't be the first if you revert to soldering the wires to the contacts. \$\endgroup\$
    – Transistor
    Mar 12, 2016 at 19:58
  • \$\begingroup\$ I've crimped JST connectors with a pair of side cutters on several occasions, you don't have to have the recommended crimper, it just does a better job, that's all. \$\endgroup\$
    – Sam
    May 15, 2016 at 0:37

1 Answer 1


There aren't really any truly universal crimp tools but if I need to use a connector of some sort where the cost of a manufacturer crimp tool isn't justified I normally go about it this way:

  • Make sure you select a wire gauge that properly matches the contacts.

  • Strip the wire and lightly crimp the two center tabs by closing them up one side at a time using a pair of regular pliers, you won't get a good crimp with pliers it just has to be enough to hold the cable in place.

  • Place a small Phillips head screwdriver (or steel rod) around the same diameter as the outer tabs designed to hold the insulated section of the cable down the length of the terminal.

  • Place it into a vise and use the force against the screwdriver / rod to make the crimp. I use a good machine vise but any metal one large enough so you can get enough force should do the job, not a small one for holding PCBs etc.

  • Then for the outer tab for the insulated section I just normally use regular pliers again for a start followed by a lighter touch towards the outside of the vise.

I've found that to work well but often also sometimes add a dash of solder as a bit of extra security as long as it doesn't interfere with the housing.


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