DELPHI FITTINGS
Product Overview
The Delphi Fittings Part 318 is a 37° JIC Tube Nut, an essential component for creating JIC flare connections with hydraulic tubing. This female nut is designed to be used in conjunction with a 37° JIC Tube Sleeve (Part #319). When assembled, the nut slides over a 37° flared tube end, and the sleeve sits behind the flare. As the nut is tightened onto a male JIC fitting, it presses the sleeve against the back of the flare, forcing the flared tube surface into tight, metal-to-metal contact with the 37° cone of the male JIC fitting, creating a reliable high-pressure seal. Manufactured from high-quality carbon steel and zinc-plated for corrosion resistance, the Part 318 JIC Tube Nut is a standard component in hydraulic systems worldwide.
Key Features & Specifications
| Material | High-Grade Carbon Steel |
|---|---|
| Thread Type | Female JIC (Unified National Fine - UNF) (per SAE J514 / ISO 8434-2) |
| Component Type | Tube Nut for 37° Flare Connections |
| Compatibility | Used with 37° flared tubing and JIC Tube Sleeve (Part #319) to connect to male JIC fittings. |
| Sealing Mechanism | Draws the flared tube and sleeve against the male JIC 37° cone to create a metal-to-metal seal. |
| Primary Function | To secure a flared tube end, with a sleeve, to a male JIC 37° flare fitting. |
| Plating & Finish | Cr3+ Trivalent Zinc Clear (ASTM B117 salt spray tested) |
| Applicable Standard | SAE J514 / ISO 8434-2 (ANSI B1.20.3 for NPTF threads) |
Commonly Available Sizes (Part #318 Series)
Delphi Fittings manufactures precision standard and jump dash sizes for Part 318. Engineering dimensions, thread specifications, and hex sizes for standard production series are detailed below:
| Delphi Part # | Applicable Tube O.D. | Thread / Connection Size | Standard Hex |
|---|---|---|---|
| 318-02 | 1/8" | 5/16-24 Thread | 7/16" |
| 318-03 | 3/16" | 3/8-24 Thread | 7/16" |
| 318-04 | 1/4" | 7/16-20 Thread | 1/2" |
| 318-05 | 5/16" | 1/2-20 Thread | 9/16" |
| 318-06 | 3/8" | 9/16-18 Thread | 5/8" |
| 318-08 | 1/2" | 3/4-16 Thread | 13/16" |
| 318-10 | 5/8" | 7/8-14 Thread | 15/16" |
| 318-12 | 3/4" | 1-1/16-12 Thread | 1-1/8" |
| 318-14 | 7/8" | 1-3/16-12 Thread | 1-1/4" |
| 318-16 | 1" | 1-5/16-12 Thread | 1-3/8" |
| 318-20 | 1/4" | 1-5/8-12 Thread | 1-11/16" |
| 318-24 | 1/2" | 1-7/8-12 Thread | 2" |
| 318-32 | 2" | 2-1/2-12 Thread | 2-5/8" |
Need custom jump sizes, extended neck lengths, special thread pitches, or alternative alloy grades (AISI 316 Stainless / Brass)? Delphi engineers and machines custom hydraulic fittings to client blueprints.
Specific Applications & Hydraulic Circuit Routing
Part 318 fittings provide reliable, high-integrity connections across demanding mobile and stationary fluid power applications:
- Industrial Hydraulic Machinery: High-pressure hydraulic circuits, power packs, and hydraulic manifolds utilizing Part 318 for reliable fluid conveyance.
- Mobile & Construction Equipment: Excavators, agricultural machinery, and heavy equipment subject to vibration, pressure pulsations, and harsh operating conditions.
- Fluid Routing & Manifold Transition: Facilitates smooth tube-to-hose or port-to-tube connections without imposing residual mechanical stress on hydraulic lines.
Installation & Assembly Guidance
- Surface & Thread Inspection: Ensure all male 37° flare surfaces, mating female cones, and thread flanks are clean, smooth, and free of burrs or contaminants.
- Finger-Tight Alignment: Align the mating connections coaxially and thread the connection by hand until fully seated finger-tight.
- Flats From Finger Tight (F.F.F.T.): Tighten the nut or hex body using the recommended SAE flats-from-finger-tight (FFFT) method or calibrated torque wrench to achieve proper metal-to-metal cone engagement.
- Dual-Wrench Backup Practice: Always support the fitting body hex with a backup wrench while tightening the mating nut or pipe connection to prevent inadvertent loosening.
Why Source Part 318 from Delphi Fittings?
- SAE J514 & ISO 8434-2 Compliance: Precision CNC machined to exacting aerospace and industrial hydraulic tolerances for 100% interchangeability with North American and international systems.
- ASTM B117 Corrosion Protection: Heavy trivalent zinc clear plating provides exceptional resistance to red rust in harsh industrial and outdoor environments.
- Rigorous Thread Inspection: Every production batch undergoes 100% go/no-go optical and mechanical thread gauge verification to ensure leak-free field assembly.
- Factory-Direct OEM & Distributor Supply: Manufactured directly at our ISO 9001:2015 certified facility in Yuhuan, China, offering comprehensive MTR traceability and volume pricing.
Get a Quote for Part 318 - 37° JIC Tube Nut
Direct OEM container-load and distributor replenishment pricing, complete material test reports (MTR), and inspection samples available upon inquiry. Connect with our engineering sales team for rapid quotations and delivery schedules.
Complementary & Mating Hydraulic Fittings
Commonly paired with Part 318 in hydraulic valve manifolds, power units, and industrial fluid power circuits:
