Hose Fittings, Adapters and Clamps

G1/4, NPT or press: reading the thread and the joint

Identify the thread before the size. G1/4 is a parallel 1/4 inch BSP thread sealed with an O-ring and is the standard port on PC liquid-cooling parts, while 1/4 NPT is tapered and sealed with tape. They differ slightly in pitch and angle, so they can start together but never seal. Press fittings, such as the carbon-steel couplings in this list, are crimped with a matching press tool.

Press systems are usually matched to one maker: the jaws, sealing rings and rated fluid, whether water or gas, must belong to the same system, so check the product line and the media rating. For tubing, fittings clamp over the outside diameter or grip the inside of soft tube, so the tube size has to be known to the millimeter.

Tube size, clamps and mixing metals in a loop

Hard tubing for a PC loop is named by outside diameter, such as 12 or 16 mm, and compression fittings are made for one tube size, so buy tube and fittings together. Soft tubing is named by inner and outer diameter, and a barb or compression collar must suit both. Hose clamps are sized by range, so choose one whose range includes the hose's outside diameter once it is on the fitting.

Finish and metal matter inside a liquid loop. Brass and nickel-plated parts, and copper radiators, are compatible with each other, but mixing them with bare aluminum risks galvanic corrosion. Fittings such as rotary adapters, extenders and dual fittings add angles and spacing, so check that the stated length leaves room between the GPU, the radiator and the case.

Questions about Hose Fittings, Adapters and Clamps

Can I use cooling fittings from different makers together?

The G1/4 port thread is standard, so fittings from different makers usually screw into the same ports. The compression collar, however, is made for one tube diameter, and finishes may not match. Buy tube, collars and fittings for one outside diameter and check the stated tube size.

How do I choose a hose clamp size?

Measure the hose's outside diameter on the fitting, then pick a clamp whose adjustment range includes that figure, ideally near the middle of the range. A clamp at the extreme end of its range tightens unevenly and may leak or cut the hose.

What is the difference between an adapter and a coupling?

A coupling joins two pieces of the same kind, while an adapter changes the connection, such as male to female or one thread standard to another. Check the gender and thread of each end, because a male-to-female adapter and a male-to-male coupling are not interchangeable.