How To Measure Flange Gaskets

Flange gaskets are generally the most common type of gasket and the one that most people will generally think of. The are almost always circular  in shape and are available with or without bolt holes depending on the requirement.

Measuring the Inner and Outer Diameters

Perhaps two of the most crucial dimensions for a flange gasket. The inner (ID) and out (OD) diameters ensure that the gasket will fit correctly in your application. The best way to get these measurements is to use either a tape measure or a ruler. Simply place the measuring tool edge to edge over the gasket face and note the measurements accordingly.

Measuring the Pitch Circle Diameter

As many flange gaskets also feature bolt holes it is important to accurately measure the gap between opposite holes. Depending on the size of the gasket the best measuring tool to use is a digital calliper as this will give the most accurate reading. You can also use a tape measure or ruler however. To calculate the pitch circle diameter you need to measure from the inside of one hole to the inside of the opposite hole. Please note, this method only works assuming both hole diameters are equal.