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J1784 straight cable-clamp, 90° cable-clamp and 90° shielded backshells
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J1784 non-clamping straight backshell with knurled nut

J1784 Backshells for 38999-Type Connectors

Straight and 90° · cable clamp 2.49–21.67 mm · 360° shield termination

J1784 backshells take the cable load off the crimp and solder joints and carry the shield through to the connector shell. They thread onto GJB 599 Series I to IV and J599WR connectors in unshielded, cable-clamp and shielded versions, straight or 90°, with anti-rotation teeth on every type.

Fits
GJB 599 Series I–IV, J599WR
Forms
Straight and 90°
Cable clamp range
2.49–21.67 mm
Shield termination
360° shape-memory band, heat-shrink or band
Materials
Aluminum, stainless steel, titanium, composite

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Key features

  • Anti-rotation interface on every backshell
  • Cable-clamp versions relieve the contact joints when the cable is under tension
  • Shielded versions terminate the braid 360° with a Ti-Ni shape-memory band, a heat-shrink boot or a steel band
  • Self-locking (anti-loosening) straight and 90° versions
  • Rain-tight versions with long bodies for mixed high- and low-frequency cable bundles
  • Composite bodies with cable seal for weight-sensitive equipment
  • J1784WR versions with nickel-fluorocarbon polymer finish for the salt-spray resistant J599WR series
  • Other outlet diameters, lengths and angles on request

Specifications

Mechanical
ParameterValueCondition
Rear thread, Series III / IVM12 × 1-7H to M37 × 1-7Hshell 9 to 25
Rear thread, Series I / II0.4375-28UNEF-2B to 1.4375-18UNEF-2Bshell 8 to 24
Cable clamp range2.49–5.49 mm (shell 9) to 10.62–21.67 mm (shell 25)J1784/38, /39
Anti-rotationYes, all types
Self-lockingJ1784/38S, /39S, HF, HG
Shielding
ParameterValueCondition
Shield terminationTi-Ni shape-memory band, heat-shrink boot or steel band
Shape-memory bandsTR-04 to TR-22, matched to the cable outlet
Band installationHot-air gun, about 45–60 s; the colour mark turns from green to black at about 165 °C
Materials and finishes
ParameterValueCondition
NAluminum alloy, nickel plated
WAluminum alloy, olive-drab cadmium
SStainless steel, passivated
TATitanium alloyJ1784/38
M / JComposite, nickel or olive-drab cadmiumcomposite types
TAluminum alloy, nickel-fluorocarbon polymerJ1784WR

GJB 1784-1993 — Chinese backshell specification, the counterpart of MIL-C-85049 (now SAE AS85049).

Values not listed above — for example vibration level, leak rate or other environmental tests — can be tested to your requirements, including third-party testing. Specifications are subject to change; contact us for the current datasheet.

Backshell selection by function

Choose the function first, then the version that matches your connector series.

FunctionGJB 599 Series I / IIGJB 599 Series III / IVForm
Non-clamping, unshieldedJ1784/27 (HA)J1784/14Straight
Cable clamp, unshieldedJ1784/49 (HB)J1784/38Straight
Cable clamp, unshielded—J1784/38SStraight, self-locking
Cable clamp, unshieldedJ1784/47 (HC)J1784/3990°
Cable clamp, unshielded—J1784/39S90°, self-locking
Cable clamp, unshielded—J1784/91 or J1784/38 (M, J)Composite, straight
Cable clamp, unshieldedJ1784/56—Straight, cable-tie type
Cable clamp, unshielded—J1784/92Composite, 90°
Cable clamp, unshielded—J1784/15Composite, straight, with cable seal
Cable clamp, unshielded—J1784/16Composite, 90°, with cable seal
Shielded, non-clampingJ1784/85J1784/88Straight, shape-memory band
Shielded, non-clampingJ1784/87J1784/9090°, shape-memory band
Shielded, non-clampingHD—Straight
Shielded, non-clamping—J1784/20 (G1, G3)90°, shape-memory band
Shielded, non-clamping—J1784/20 (G2, G4)Straight, shape-memory band
Shielded, non-clampingJ1784/62J1784/69Straight, heat-shrink boot
Shielded, non-clamping—J1784/20Straight, steel band
Shielded, non-clamping—J1784/20 (M, J)Composite, straight, steel band
Shielded with cable clampHEHE-MStraight
Shielded with cable clampHF—Straight, self-locking, shape-memory band
Shielded with cable clampHG—90°, self-locking, shape-memory band
Shielded with cable clamp—HK-M90°
Shielded with cable clampJ1784/17G1J1784/18Straight, rain-tight
Shielded with cable clampJ1784/76J1784/7990°, rain-tight
Shielded with cable clampJ1784/62G1—Straight
Shielded with cable clampJ1784/62G2—90°

Cable clamp range, Series III / IV (J1784/38)

ShellRear threadCable Ø min (mm)Cable Ø max (mm)Ø A max (mm)Length B max (mm)
09M12×1-7H2.495.4916.522.15
11M15×1-7H3.895.9419.022.15
13M18×1-7H4.838.3322.820.65
15M22×1-7H6.6011.6125.826.65
17M25×1-7H7.1915.6029.226.65
19M28×1-7H8.2616.1032.028.15
21M31×1-7H8.7117.7435.128.15
23M34×1-7H9.6820.9038.233.30
25M37×1-7H10.6221.6741.534.05

The same clamp ranges apply to J1784/38S, J1784/39, J1784/39S and the J1784WR versions; overall lengths differ.

Cable clamp range, Series I / II (J1784/49)

ShellRear threadCable Ø min (mm)Cable Ø max (mm)Ø A max (mm)Length B max (mm)
080.4375-28UNEF-2B2.495.9415.6020.80
100.5625-24UNEF-2B3.895.9418.6020.80
120.6875-24UNEF-2B4.838.3321.7919.30
140.8125-20UNEF-2B6.6011.6124.9525.30
160.9375-20UNEF-2B7.1915.6028.2025.30
181.0625-18UNEF-2B8.2616.1030.9026.80
201.1875-18UNEF-2B8.7117.7334.1026.80
221.3125-18UNEF-2B9.6820.9037.6632.05
241.4375-18UNEF-2B10.2621.6740.4632.80

Versions

Series codeVersionNotes
J1784Standard backshells for GJB 599 Series I to IV
J1784WRSalt-spray resistant backshells for J599WRTypes 14, 38, 38S, 39, 39S, 88, 90, 20, 20G1–G4, 69, 18, 79, HE-M and HK-M in finish T
J1784FSBackshells for the IP67 J599FS seriesSee the J599FS page

How to order

J1784/[type]-[shell][finish]

Example: J1784/38-15N — Straight cable-clamp backshell for a Series III shell 15 connector, aluminum with nickel

Code segmentOptions
Type
  • 14 Straight, non-clamping (Series III / IV)
  • 38 / 38S Straight cable clamp / self-locking (Series III / IV)
  • 39 / 39S 90° cable clamp / self-locking (Series III / IV)
  • 88 / 90 Shielded straight / 90°, shape-memory band (Series III / IV)
  • 69 Shielded straight, heat-shrink boot (Series III / IV)
  • 18 / 79 Shielded rain-tight straight / 90° with cable clamp (Series III / IV)
  • 27 / 49 / 47 Non-clamping / straight clamp / 90° clamp (Series I / II)
  • 85 / 87 Shielded straight / 90°, shape-memory band (Series I / II)
Shell
  • 09–25 Series III / IV shell (letter codes A–J also used) or Series I shell
  • 08–24 Series II shell
Finish
  • N Aluminum, nickel
  • W Aluminum, olive-drab cadmium
  • S Stainless steel, passivated
  • TA Titanium alloy (J1784/38)

Shielded types 88 and 90 add A when a shape-memory band is included, followed by the band code; without a band the code gives the cable outlet diameter.

J1784WR backshells for the J599WR series use finish T (for example J1784WR/14-25T).

J1784 and J1784A designate the same parts; hyphens and spaces in the part number are placeholders only.

Typical applications

  • Rail vehicles and signalling
  • Marine and offshore equipment
  • Industrial automation and robotics
  • Test and measurement systems
  • Power and energy equipment

Frequently asked questions

Which backshell do I need?

Use a cable-clamp type when the cable is under tension, a shielded type when the braid must reach the connector shell, and a combined shielded clamp type for both. Send the connector part number, cable diameter and exit angle and we will propose the part number.

Do these backshells fit other 38999-type connectors?

They are made to the GJB 1784 interface for GJB 599 connectors. For other connectors, send the part number and we will propose the matching backshell and samples for your fit test.

How is the shape-memory band installed?

Place the band over the braid and heat it evenly with a hot-air gun for about 45 to 60 seconds. It is fully shrunk when the colour mark turns from green to black, at about 165 °C.

How should a backshell be secured against loosening?

Use at least one method: lock wire through the nut holes, thread-locking adhesive on the connector rear thread, heat-shrink sleeve over the whole backshell, or thread-locking adhesive on the set screw.

From sample to production

  1. Send your requirement

    Part number, drawing, pin-out or a short description of your application.

  2. Configuration and quote

    Our engineers match the configuration and reply with a drawing and quotation.

  3. Samples

    Samples are made to your order. Third-party testing to your specification is available on request.

  4. Your approval

    You test the samples in your own equipment and approve them.

  5. Series production

    Production follows the approved sample configuration.

Need a quote or a drawing?

Send your part number, pin-out or drawing. An engineer will reply by email.

Request a quote

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