How to Measure Rod Ends

This guide is provided to assist with measuring Rod Ends to make selecting the correct size easier.

Imperial Thread

All our imperial sized Rod Ends use the Fine Unified Thread Standard referred to as “UNF”. The method used to identify the thread pitch is Threads Per Inch (TPI). It is simply a count of the number of threads per inch measured along the length of the threaded rod. The diameter of the outer edge of thread represents the Thread Size. You are aiming for the same measurement location when measuring the diameter of a female rod end.

Thread Size - Diameter	UNF Threads Per Inch
3/16	32
1/4	28
5/16	24
3/8	24
7/16	20
1/2	20
5/8	18
3/4	16
7/8	14
1	12
1 1/4	12

 Metric Thread

Our metric sized Rod Ends are specified by a thread pitch instead of a thread count. The thread pitch is the distance between threads expressed in millimeters (measured along the length of the threaded rod). For example a thread pitch of 1.5 means that the distance between one thread and the next is 1.5mm.

Thread count or pitch is normally measured using a Thread Gauge, these are a relatively inexpensive tool.

The Rod Ends we offer use five possible thread pitches 1.0, 1.25, 1.5, 1.75, 2.0 and are detailed when selecting your chosen Rod End.

Ball Eye

The eye is easily measured across the diameter of the hole.