02/06/2026
A gasket that's 1mm out in the wrong dimension won't seal. Getting the measurement right before you order is the single most important step in the process.
Here's what you need:
Inner diameter (ID) — the bore of the gasket, which must match the pipe bore or fitting opening.
Outer diameter (OD) — the outside edge of the gasket. Must sit within the fl**ge face without overhang.
Thickness — determined by the fl**ge facing type and the compression range of your chosen material.
Bolt holes — measure the pitch circle diameter (PCD), the diameter of each bolt hole, and the number and spacing of holes.
The most common errors: measuring the gasket OD and treating it as the pipe size, or measuring a worn or compressed gasket without accounting for deformation. Always measure from undamaged reference surfaces where possible.
If you're unsure, our team can help interpret your measurements. Or send us the worn gasket and we'll digitise it for you.
Call us on 01425 278011 or visit gaskets-direct.co.uk