Clip off the center core to the proper length for the connector being used. The connector packaging or data sheet should have this specific measurement. In the case of this connector, we clipped it to 3/16 of an inch. If the center conductor is too short or too long, the connector shell will not seat correctly. Figure 1-18 shows the relative length for an N-Male connector. After trimming back the core, remove any ridges or burrs around the cut edge. This will allow the pin to seat properly.

Place the center pin onto the conductor as shown in Figure 1-19. Ensure the center conductor bottoms out at the first stop of the pin. Also, ensure the pin rests within 1–2 mm of the foam dielectric.

This is the first of two crimps for the connector. Ensure your crimp tool has the correct die for the type of cable and connector being used. For LMR-400, the crimp tool should have a die with hex sizes of 0.429 for the outer ring, and 0.128 and 0.100 for the center pins.

Place the pin into the crimp tool as shown in Figure 1-20. The bottom edge of the pin usually will have a small ridge to help line it up and keep the pin seated on the core. Crimp down with even, strong pressure. If your crimp tool has the ratcheting feature, it will apply only the necessary amount of pressure before releasing.

Figure 1-21 shows a properly crimped center pin. Notice the marking around the edges where the crimp actually clamped the pin to the center conductor.

It’s time to place the connector body over the pin. Figure 1-21 shows the connector about to slide onto the pin. Before continuing, be very sure that the crimp ring from Step 2 is still waiting for you down the cable behind the splayed out shield before you place the connector body onto the cable.

Ensure the crimp ring is on the cable before snapping the connector shell into place. Once the shell is snapped into place, it will be difficult to remove. Also, removing and replacing the shell would degrade the cable performance. If the ring is not in place, you’ll need to cut the connector off and rebuild the cable with a new connector.

connector mates with the pin. This mating is meant to hold the connector on the pin until the last crimp. Tug lightly at the connector like you are going to pull it back off. It should stay in place under light pressure. If forced or yanked, it may come off, so be gentle.

Figure 1-22 shows the connector fully inserted with the shield still pulled back. Notice that the center pin does not extend past the inner ring of the connector.

Fan out the shield strands and trim down with scissors, as shown in Figure 1-23.To help cleanup, hold the cable over a wastebasket. The goal is to trim down the shield but still have enough to fit under the crimp ring.Trim the shield down to about a quarter of an inch.

Shield strands are made of steel. The thin wires can pierce the skin like a needle in some circumstances. Make sure to handle the waste strands with care, and clean up the area to minimize the chance of accidents.

Now pull up the crimp ring you placed in Step 2. The shield will slip under the crimp ring and should be splayed out evenly around the connector body, as shown in Figure 1-24. If the shield is still too long, move the crimp ring out of the way and trim a little more of the shield with the scissors.Try to get just enough shield under the crimp ring, but not sticking out past the ring.

Finally, it’s time to crimp the crimp ring onto the cable. This is the second of the two crimps needed to make the cable. As in Step 9, use the crimping tool. But this time crimp with the larger diameter hex size of 0.429. Place the tool at the upper edge of the crimp ring, butted against the connector body as shown in Figure 1-25. Crimp with strong, even pressure, and only crimp once, just like in Step 9.

Now that the cable is complete, it’s time for a visual inspection. Check the back of the connector at the seam of the crimp ring. If there are any shield strands sticking out, cut them off with the razor blade, as shown in Figure 1-26.

That’s it! Now repeat steps 1 to 12 for the other end of the cable. After doing a few of these, it will become second nature.With practice, building a cable connector can take just a few minutes.