---
title: "What Are JIC 37-Degree Flare Fittings Used For?"
description: "JIC 37-Degree Flare Fittings (SAE J514 / ISO 8434-2 (37-degree flared connections)) are used for joining and sealing fluid or pneumatic lines."
url: https://engineeringhardware.com/applications/jic-flare-fittings/
source: Engineering Hardware & Fasteners
---

# What Are JIC 37-Degree Flare Fittings Used For?

Pipe & Pneumatic Fittings · SAE J514 / ISO 8434-2 (37-degree flared connections) · Application guide

Typical applications, the industries that specify jic 37-degree flare fittings, and how to choose the right size, material and finish for the joint.

JIC 37-Degree Flare Fittings are used for joining and sealing fluid or pneumatic lines. They are manufactured to SAE J514 / ISO 8434-2 (37-degree flared connections), and selection is driven by the pipe thread size, the fit and tolerance the assembly requires, and the service environment.

- **Primary duty:** Joining and sealing fluid or pneumatic lines
- **Governing standard:** SAE J514 / ISO 8434-2 (37-degree flared connections)
- **Pipe thread size range:** -04 to -20
- **Category:** Pipe & Pneumatic Fittings

Application notes are general engineering guidance. Verify the property class and any approval requirement against your own design calculation.

![What Are JIC 37-Degree Flare Fittings Used For? application image](https://engineeringhardware.com/wp-content/uploads/2026/09/JIC-Flare-Fittings.webp)

The primary duty of JIC 37-Degree Flare Fittings is joining and sealing fluid or pneumatic lines. Below: the sectors that specify them in volume, the checklist used to select the right size and material for the application, installation notes, and the known limits of the type. Stocked across roughly 4 to 20, they cover general to heavy-duty work.

## Typical Applications for JIC 37-Degree Flare Fittings

The most common settings where these are specified:

- **Fabrication & metalwork:** bench and on-site assembly of steel frames, enclosures and weldments.
- **Pneumatic systems:** connecting air lines, cylinders and valves on automation rigs.
- **Hydraulic & fluid power:** sealed, pressure-rated joints in fluid lines.
- **Process & plant piping:** tapped connections on manifolds and equipment.
- **General machine building:** fastening covers, brackets, motors and sub-assemblies on production equipment.

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## How to Specify JIC 37-Degree Flare Fittings for Your Application

- **Size:** Match the nominal size to the mating thread or hole. This product spans 4–20; check the full table below for the exact dimensions of each size.
- **Thread & pressure:** Match the thread form (BSP/NPT/metric) and pressure rating to the line, and seal appropriately (tape, sealant or O-ring).
- **Environment:** For damp, coastal or chemical exposure prefer A4/316 stainless or a suitable coating; indoors, plated steel or A2 is usually sufficient.
- **Standard:** This product is supplied to SAE J514 / ISO 8434-2 (37-degree flared connections). Quoting the standard on your order guarantees interchangeable dimensions between suppliers.

## Installation & Assembly Practice

- Seal tapered threads with PTFE tape or anaerobic sealant applied clear of the first thread; parallel threads seal on a washer or O-ring, not on the thread.
- Tighten to the fitting manufacturer's torque — over-tightening tapered threads splits female ports.

## Common Selection Mistakes with JIC 37-Degree Flare Fittings

- Mating BSP and NPT threads directly — the 55°/60° forms do not seal against each other.
- Exceeding the pressure rating of the lowest-rated component in the line.

## Where JIC 37-Degree Flare Fittings Are Not the Right Choice

Do not mix thread forms (BSP into NPT) without an adapter, and do not exceed the pressure rating of the lowest-rated component.

Custom manufacturing · Made to drawing

## Need a JIC 37-Degree flare fittings outside the standard range?

A non-standard pipe & pneumatic fitting is quoted from the drawing; where one already exists in the catalog, the special is usually a variation on its tooling.

Minimum order from 2,000 pieces; samples within 7 days of drawing approval.

[Custom pipe & pneumatic fitting manufacturing](https://engineeringhardware.com/custom/fittings/)[Send a drawing](https://engineeringhardware.com/custom/fittings/#rfq)

## Technical Drawing

Dimensioned line drawing of -04 JIC 37-Degree Flare Fittings to SAE J514 / ISO 8434-2 (37-degree flared connections). Side view and top view, drawn to the dimensions in the table below and redrawn for any size selected.

- **Tube outside diameter:** 1/4 in
- **Thread (UNF):** 7/16-20
- **Cone angle:** 37 degrees

## Dimensions & Specifications (SAE J514 / ISO 8434-2 (37-degree flared connections))

| Dash size | Tube outside diameter | Thread (UNF) | Cone angle |
| --- | --- | --- | --- |
| -04 | 1/4 in | 7/16-20 | 37 degrees |
| -05 | 5/16 in | 1/2-20 | 37 degrees |
| -06 | 3/8 in | 9/16-18 | 37 degrees |
| -08 | 1/2 in | 3/4-16 | 37 degrees |
| -10 | 5/8 in | 7/8-14 | 37 degrees |
| -12 | 3/4 in | 1-1/16-12 | 37 degrees |
| -16 | 1 in | 1-5/16-12 | 37 degrees |
| -20 | 1-1/4 in | 1-5/8-12 | 37 degrees |

Inside the plant

## Manufactured in our own plant

This part is cold-formed, threaded, heat-treated and finished in-house. The stages below are where its class and finish are actually decided.

1. ![Wire rod feeding into a cold heading machine](https://engineeringhardware.com/wp-content/uploads/2026/08/09-wire-rod-feed-cold-heading-machine.webp) 01 **Cold heading** Wire rod is drawn to size and cold-formed into blanks. Forming rather than cutting keeps the grain flow continuous around the head, which is where a bolt is most likely to fail. Head dimensions and under-head radius checked at set-up and per shift.
2. ![Thread rolling machine producing bolt threads](https://engineeringhardware.com/wp-content/uploads/2026/08/03-thread-rolling-machine-bolt-production.webp) 02 **Thread rolling** Threads are rolled between hardened dies rather than cut. Rolled threads are stronger in fatigue than cut threads and hold pitch and flank angle far more consistently across a batch. Go / no-go ring gauges to ISO 965 tolerance class 6g.
3. ![Baskets of bolts staged for heat treatment](https://engineeringhardware.com/wp-content/uploads/2026/08/05-heat-treatment-baskets-black-bolts.webp) 03 **Heat treatment** Quench-and-temper brings carbon and alloy steel to the property class ordered — 8.8, 10.9 or 12.9 — with the furnace charge tracked so a finished lot can be traced back to it. Core hardness and tensile tested per lot to ISO 898-1.
4. ![Zinc plated bolts in a treatment basket](https://engineeringhardware.com/wp-content/uploads/2026/08/23-zinc-plated-bolts-treatment-basket.webp) 04 **Surface treatment** Zinc, zinc-nickel, hot-dip galvanizing, black oxide, phosphate and Dacromet, selected against the service environment rather than against the price list. Coating thickness and neutral salt spray hours to ISO 9227.

## Frequently Asked Questions

### How do I choose the right size of JIC 37-Degree Flare Fittings?

Match the nominal size to the mating thread or hole. This product is available from 4 to 20; the full dimension table on this page lists each size.

### Can I mix BSP and NPT JIC 37-Degree Flare Fittings?

Not directly — the thread forms differ in angle and taper. Use a dedicated BSP-to-NPT adapter, and seal with the method suited to the thread (tape, sealant or O-ring).

### What material should JIC 37-Degree Flare Fittings be for outdoor use?

For damp, coastal or chemical environments specify A4 (316) stainless or a suitably coated steel. For indoor or dry use, A2 (304) stainless or zinc-plated steel is normally adequate.

### Are JIC 37-Degree Flare Fittings made to a recognized standard?

Yes — they are manufactured to SAE J514 / ISO 8434-2 (37-degree flared connections), so dimensions are interchangeable between suppliers when you quote the standard on your order.

### Can I get a quote for JIC 37-Degree Flare Fittings in the size and material I need?

Yes. Use the technical drawing and quote form on this page to set the size and options, then send the exact configuration to our team for pricing and lead time.

## Related Pages

Product page: [JIC 37-Degree Flare Fittings — specifications & sizes](https://engineeringhardware.com/fastener/jic-flare-fittings/)

### JIC 37-Degree Flare Fittings Specification Guides

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