Thread & fitting identification

A mixed fleet forces you to join families that were never meant to meet. Where that is ordinary engineering, where it becomes a leak with a schedule, and how to design it out at the next hose change.

A board of known samples on the wall answers in five seconds what a catalogue answers in twenty minutes. What to put on it, how to label it, and what to keep off it.

No seat gauge, no pitch gauge, a machine down and a phone with two bars. What a caliper and a known bolt will actually tell you, and what to send.

Workshops ask which standard "we use here". Countries do not have thread standards — they have import histories, and the drawer should be stocked for the fleet rather than the flag.

These machines sit between the Japanese and European worlds, and the honest answer is that a single machine can carry both. What that means for how you identify and how you stock.

Metric 24° cone covers most of it, but the same tube size exists in two series with different threads. Knowing which one you are holding is the whole job.

JIC, ORFS, NPT, O-ring boss and split flanges arrive as a set. What each is for, which two are routinely confused, and the mistake that ruins a port rather than a fitting.

Tractors sit further from a hydraulics counter than any other machine, and the repair happens when the rain is coming. What to hold, and what to identify before you need it.

Two common families share a 30° seat and use different threads underneath it. Checking the angle alone tells you they match, and they do not — here is how to separate them.

Metric 24° cone and BSP cover most of what you will meet, with flanges on the big lines. What each looks like in the hand, and why the badge on the machine never settles it.

Adapter stacking: when it is fine, and when it is the leak

Everyone stacks adapters. Nobody writes down where it stops being acceptable, so here it is — three rules, and the one arrangement that is always wrong.

BSPP bonded seals and dowty washers: getting the size right

A bonded seal is sized by the thread it sits under, not by the bore of the fitting or the size printed on the box. That one sentence resolves most of the confusion.

Photographing a fitting so someone can identify it without holding it

Four photographs and one measurement identify almost any hydraulic fitting remotely. Most requests arrive with one photograph taken at arm’s length, and that one settles nothing.

Thread size and pitch, by family: the reference table for the bench

JIC 9/16"-18 and ORFS 9/16"-18 are the same thread. They will assemble, and one of them will leak. Every designation and pitch we stock, grouped by family, with the collisions marked.

JIC vs ORFS vs NPT vs BSP: the four connector families, compared

Four families cover almost every hydraulic connection you will meet. What each one seals on, which are re-makeable, and which pairs will thread together and still fail.

BSPP vs BSPT: why a parallel thread needs a seal and a tapered one does not

They share a thread form and a size designation, and they do not seal the same way. How to tell them apart on the bench, and what happens when they are mixed.

How to identify any hydraulic fitting in four steps

Four thread families cover almost everything on a machine in the Gulf. Here is how to tell them apart with a caliper and a thread gauge — and why two of them will thread together and still leak.