Some needle-nose pliers have the right crimping notches - the longer tabs should be bent down and into the insulation, the shorter tabs fold into the bare wire. It's a good idea to then put heat shrink tubing on. The correct crimping tool will do that folding motion. See the small thing that sticks up:
Ideally, you want the crimp tool made specifically by the manufacturer of the connector. While the basic design is 'generic', there can be variations from manufacturer to manufacturer, many times enough so that they won't quite crimp right with a 'generic' tool. With that said, this is a 'Packard' type crimp and there's plenty of this style crimper available in the aftermarket. These were/are used mostly by the OEMs, but they use extremely expensive power crimpers to get good repeatable crimps with very few failures. The hand-held versions can be tricky to use, and most require two operations; one to crimp onto the bare conductors, a second to crimp to the wire insulation for strain relief. The 'better' crimps have points on the larger 'flags' to penetrate/grip the wire insulation securely. Expect to have some failures until you get the hang of it. I avoid these like the plague... A comprehensive discussion is here.... https://www.jalopyjournal.com/forum/threads/crimping-tutorial.1127519/
I love those connectors, and use them in harnesses, every single day, at work. Ratcheting crimpers made by AMP or Molex work best, but well-rated ones from that giant internet retailer should work just fine. These have a two-step die, that crimps both sections, at the same time. I make hundreds in one week. I use glue lined heat shrink over the crimp, to prevent corrosion.
I like the ratcheting style that gimpy posted. I use them for "weather pack" style connectors, which have a very similar crimp flange as the piece you've posted, except they have two smaller tabs for the wire instead of 1. As mentioned, the longer tabs should wrap around the insulation/case of the wiring, the shorter tabs should crimp into the wire strands themselves. You don't need to strip much insulation off.
The trick with these is to use a quality connector as well as a quality crimper. Experience helps too. I've used these also while I was still working but my experience is they're not 'amateur friendly'. I do know that the connector manufacturers would not guarantee connector integrity if a 'generic' crimper was used; you had to have an 'approved' tool...
It might help some of the guys if one of you shows which side up to get a proper crimp That's half of it on any wire crimping though.
I work for, and crimp them for a little company that makes a few cars a year, in a prototyping division, that goes by the two letter initialism GM. The only specification is for die shape, and clamping pressure. The manufacturer of the tool is irrelevant, per our specs.
Thanks for the great info., the only reason I am using these particular ones is I am trying to replace some wires in the stock harness and need this style that "locks" into the plug. I do kinda enjoy replacing a circuit and making it look "factory" I may have a set of those crimpers you showed, have to dig around and see...
This crimper. Designed for those Packard 56 terminals. Not inexpensive, but easy to use, and makes perfect crimps every time. Talk to Ed at Great Plaines Electronics if you want one. Nice guy, good prices. https://www.greatplainselectronics.com/ Sent from my iPad using The H.A.M.B. mobile app
Advanced Auto Parts has a very good crimp tool for around $30. It does bare terminals and ones with insulation. It does ratchet and is adjustable. Want a real good wire stripper? Lowes has a nice one for around $26.
Probably overkill, but I crimp them as best I can with the array of crimpers I have in the tool box. Then I touch them with a bit of solder before the heat shrink (unless they are sliding and locking into a connector, then they don't get the heat shrink).