Field notes, sizing guides and component teardowns — written by engineers, for engineers.

The fitting is cheap and the thing it screws into is not. How to judge what is in front of you, and the cases where the honest answer is that it is finished.

A seized joint is decided months earlier, at the moment somebody made it up. What that person could have done differently, and what they could not.

Both faults leak, and the marks they leave are different. What to look for on a joint somebody else assembled, and which of the two is the expensive one.

A weep is evidence before it is a fault. Where the oil appears — at the seat, down the thread, under the nut — narrows the cause to one of four things.

A factory is the one environment where the thread population is a choice rather than an inheritance. Most plants never make that choice, and pay for it every week.

There is a real domestic supply chain here, which changes the question. Local is usually right — these are the specific cases where it is not.

A mill runs flat out for months and then stops dead. Everything about stocking, inspection and replacement follows that calendar rather than the failure rate.

Container handling runs around the clock in the most corrosive air on the continent. That combination decides the material, and it decides when you are allowed to change anything.

A drilling rig is a workshop that relocates every few weeks, usually further from help each time. What travels with it decides whether a failure costs hours or a fortnight.

Crushing plant destroys joints rather than hoses. Which means the fix is joint count, clamping and torque discipline — not a heavier grade of hose.

A tractor, a backhoe, a tipper and a generator in one yard is the normal African workshop. Four origins, three thread families and one drawer that has to cover all of it.