How To Measure a Gasket

by Jonny Paulton | August 25, 2023

Gaskets can come in all shapes and sizes and serve to fill a space between two surfaces in order to create a seal.

The most common form is a full face flange gasket. These are generally circular and can either be solid or contain bolt holes.

Full Face Flange Gasket – Solid

Thickness
OD = Outer Diameter
ID = Inner Diameter

Simply place your measuring tool (ruler, measuring tape, calipers) on one edge and measure to the opposite edge.

Full Face Flange Gasket – Bolt Holes

Thickness
OD = Outer Diameter
ID = Inner Diameter
Hole Diameter

Simply place your measuring tool (ruler, measuring tape, calipers) on one edge and measure to the opposite edge.

PCD = Pitch Circle Diameter

The pitch circle diameter is the diameter of the invisible circle that passes through the centre of all of the bolt holes, and can be found by measuring the distance from the centre of one bolt hole to the centre of the opposite bolt hole. If there are an odd number of bolt holes so there aren’t any opposite each other, measure from the centre of one bolt hole to the very centre of the gasket (the inner bore), then double it.

Another common form of gaskets are a square or rectangular type, sometimes referred to as picture frame gaskets. Again, these can be solid or contain bolt holes.

Square / Rectangular Gasket – Solid

Thickness
Outside Length
Inside Length
Outside Width
Inside Width

Simply place your measuring tool (ruler, measuring tape, calipers) on one edge and measure to the opposite edge.

Square / Rectangular Gasket – Bolt Holes

Thickness
Outside Length
Inside Length
Outside Width
Inside Width
Hole Diameter

Simply place your measuring tool (ruler, measuring tape, calipers) on one edge and measure to the opposite edge.

Hole Centre
The hole centre is, essentially, the hole spacing. It is measured from the centre of one bolt hole to the centre of the hole next to it.

At RubberSmart, we are able to manufacture and cut gaskets from a range of rubber materials. If you have a custom requirement, drop us an email at info@rubbersmart.co.uk with either a drawing or a description with material required, thickness, OD, ID, number of holes, and PCD, where approriate. For more complex designs, we will require an AutoCAD drawing.