I keep posting information on crimpers and crimping, so I’m just going to put this here so I can refer to it without having to type it all in again 🙂
Crimping is a far more specialized and precise operation than it appears at first glance.
First, you need good quality tooling. Crimp dies have to be made specifically for the terminal to work ideally and wire length and wire insulation thickness are critical. That said, I have had fairly good luck with some cheap crimpers, but it’s hit and miss.
If you find that you’re having to “pre-crimp” anything before you can get the terminal into the die, then that’s a problem. That suggests that the die you have is not made for that terminal. Likewise, if the wires are slipping out. A good crimp cold welds the wire to the terminal and should require pounds of force (at least a firm pull) before the wire pulls out.
The basic technique is to put the terminal into the die and squeeze the crimper just enough to hold it in place. Next, put the stripped wire into the terminal, making sure it’s at the right depth and that the insulation ends at the right spot.
Then squeeze until the crimper completely closes and the ratchet releases so you can open it again. Inspect the crimp (the book I link below shows what various crimps should look like), and pull gently on the wire, holding the terminal in your other hand. A crimp for wire around 26-22gage should withstand at least a 5-lb pull, ideally a lot more, before it separates.
This book has everything you need to know about crimping and more.
Molex/TE Connectivity actually has a shorter book with good tips about crimping, but I can’t find it online at the moment.
If you'd like to subscribe to this blog, please click here.