D38999/26FF18PN MIL-DTL-38999 Series III Plug with Electroless Nickel Plating and Triple-Start Threaded Coupling for Aerospace Applications

D38999/26FF18PN Straight Plug, MIL-DTL-38999 Series III / GJB599 Series III

The D38999/26FF18PN is a triple-start threaded circular electrical connector plug designed for aerospace, avionics, and industrial platforms. It conforms to MIL-DTL-38999 Series III / D38999 requirements and is interchangeable with the J599/26FF18PN designation used in GJB599 Series III supply chains.
This straight plug features Class F electroless nickel finish, shell size F (shell size 19), insert arrangement F18 / 19-18, pin contacts (P), and normal keying (N). Arrangement F18 is less commonly listed for shell size 19 than standard layouts such as F11, F13, F28, F32, and F35—confirm the exact contact count and contact sizes from the Series III arrangement chart before ordering tooling or mating hardware. (Arrangement 18 is more typically associated with shell size D as D18 / 15-18.)

Product Features

• Conformant to MIL-DTL-38999 Series III / D38999 (equivalent to GJB599 Series III / J599)
• Interchangeable with cross-reference part number J599/26FF18PN
• Triple-start threaded self-locking coupling for high-vibration retention
• Straight plug style for cable-end termination
• Class F electroless nickel shell finish for corrosion resistance and conductivity
• Pin contact configuration (P) with insert arrangement F18 / 19-18 (confirm contact layout from chart)
• Normal keying (N) for standard polarization and anti-mismatch mating

Technical Specifications - D38999/26FF18PN

Part Number Breakdown

Arrangement note: F18 / 19-18 is uncommon for shell size 19 versus standard layouts such as F11, F13, F28, F32, and F35. If your drawing intended arrangement 18 in shell size D (D18 / 15-18, typically 18 x #20), verify the shell letter before purchase. Related finish options: D38999/26WF18PN (cadmium W); D38999/26KF18PN (stainless K); socket versions use S contacts; mating receptacles are typically D38999/20FF18SN or /24FF18SN. There is no functional difference between D38999 and J599 prefixes for form-fit-function mating within the same Series III family.

Compatible Applications

The D38999/26FF18PN straight plug is intended for platforms that require EMI-capable threaded interconnects in shell size 19 with arrangement 18. Typical use cases include:

• Aircraft and helicopter wiring harness cable ends
• Avionics LRUs, radar, and communication equipment
• Ground vehicles and rugged electronic enclosures
• Shipboard and outdoor equipment requiring sealed circular connectors
• Industrial systems that standardize on D38999 / GJB599 Series III interfaces

Selection Guide

Installation Notes

• Verify shell size, insert arrangement, contact gender, finish class, and keying before mating.
• Confirm F18 / 19-18 contact count and sizes from the Series III arrangement chart before selecting crimp tooling.
• Select and install a compatible M85049 / GJB1784 backshell or strain relief for shell size 19.
• Fully engage the triple-start threaded coupling until the self-locking mechanism is seated.
• Mate only with Series III receptacles of the same shell size, arrangement, opposite contact gender, and matching keying.

Why Choose D38999/26FF18PN

Form-Fit-Function Compatibility

Choosing D38999/26FF18PN ensures form-fit-function compatibility with J599/26FF18PN supply chains while meeting MIL-DTL-38999 Series III requirements. Confirm arrangement F18 against your drawing and the Series III chart so mating halves and tooling match the intended contact layout.

Ordering Information

Order by the D38999 designation D38999/26FF18PN, or cross-reference as J599/26FF18PN, depending on your procurement standard. When requesting a quote, please confirm arrangement F18 versus common shell-F alternatives (F11 / F13 / F28 / F32 / F35) or D18 / 15-18, mating receptacle part number, backshell / accessory needs, contact plating, and required quantity.