What This Outer Ferrule Does in an AMPLIMITE HDP-20 Build
The 3-745130-9 is an outer ferrule from the TE Connectivity AMPLIMITE HDP-20 series, designed to fit D-sub connector sizes from DB15 up to DB37. It crimps over the cable jacket and the inner ferrule to provide strain relief and shield termination for the cable assembly. This is the part that clamps the cable bundle so the contacts don't take the pull — one of those pieces you don't think about until a loom starts failing at the backshell.
Covers DB15 Through DB37 — One Ferrule for the Range
The 3-745130-9 outer ferrule covers the full DB15 to DB37 position range in the AMPLIMITE HDP-20 family. That means a single part number handles the cable clamp for a 15-position, 25-position, or 37-position D-sub, as long as the cable diameter falls within the ferrule's crimp range. No need to stock separate ferrules for each shell size.
Inner vs Outer Ferrule — What's the Difference?
In an AMPLIMITE HDP-20 crimp D-sub assembly, the inner ferrule crimps over the braided shield and drain wire, while the outer ferrule (3-745130-9) crimps over the cable jacket and the inner ferrule. The outer ferrule provides the mechanical grip on the cable and completes the shield path to the backshell. If you're rebuilding a DB25 loom, you need both ferrules — the inner one for the shield, the outer one for the pull strength.
Crimping the 3-745130-9 Ferrule
The 3-745130-9 outer ferrule is crimped using a standard AMPLIMITE crimp tool — typically a hex-die or indent-style tool sized for the ferrule outer diameter. The ferrule slides over the cable jacket after the inner ferrule and contacts are terminated. A proper crimp leaves the ferrule tightly formed around the jacket without cutting into the insulation. No special tooling beyond what's already in a D-sub harness shop.