A Crimp In Time Saves Nine

Upon proving the quality of your crimps, slide the shrink wrap back over the terminal's barrel and apply heat. Probably the most reliable source is a heat gun; however, heat from a butane lighter or a propane torch works just as well. Make sure to use only the heat, and not the flame itself. For what it's worth, adhesive-lined tubing very effectively seals the joint from moisture.

Due to their greater crimp pressure capacity, ratchet-style dies often feature wider jaw contact area than pliers-type tools. Furthermore, each station in most ratchet-style dies also features a secondary station with rounded jaws. They crimp the extended barrels exclusive to double-crimp terminals.

Insulated-barrel terminals operate on the same crimping principle as their bare brethren, but the tooling differs. In this case, they rely on pliers with shallower jaws, similar to those on this Molex pliers-style multi-function tool. While these simple pliers will get the job done in a pinch, they're not necessarily the tool you'd reach for to wire a whole car.

Most people refer to double-crimp terminals as strain-relief terminals, since their secondary larger barrel crimps to the wire's insulation, thereby relieving the strain on the unsupported conductor. From left to right are a standard vinyl-insulated terminal, a double-crimp terminal with its nylon insulation intact, and a similar terminal stripped of its insulation. Ken Whitney suggested we pay the small premium for nylon-insulated terminals; nylon resists higher temperatures and doesn't become brittle, as PVC (vinyl) insulation often does.

Once again, give the terminal a good tug to verify its installation. For what it's worth, this editor never considered using insulated terminals in the past specifically because ordinary pliers-type tools generated unreliable crimps despite the wrist-damaging hand pressure they require. Suffice it to say, shop time spent with a ratcheting crimp tool changed that.

Orient the terminal over the stripped wire (same method as described earlier) so either of the die's jaws squarely strikes the seamed side of the barrel. If using a ratchet-style tool with secondary crimping pockets, make sure the primary jaws, or the flatter of the two sets, generate the actual crimp close to the terminal's working end. In such cases, ensure that the secondary jaws crimp the remainder of the barrel.