Time-Serts are part of the engineering family commonly known as threads or “screw threads”. Time-Serts are called “thread inserts”. The most familiar members of the screw thread family are nuts and bolts and to talk about any thread you need to know accurately the “pitch” and the “diameter”. These elements are illustrated on the bolt pictured below
Diameter: This needs to be measured with a precision caliper or micrometer to be sure what thread you have
An example of how a METRIC THREAD is described is: either 10mm x1.5 or M10x1.5 (both terms mean the same thread) which is 10mm diameter and 1.5mm thread Pitch” as pictured by above.
This “pitch 1.5mm is the distance between
each hill or peak on the thread as pictured
IMPERIAL or “INCH” threads are described differently for example: 3/8″-16 UNC or 3/8-16 BSW
3/8 is the diameter and 16 is the Pitch [b] (as per picture above). But in the “inch” system pitch is said to be so many
threads to every inch of thread length (In the example above this is 16 threads per inch). Threads per inch is also
abbreviated to its initials “tpi” for short So, the “INCH” system describes pitch as the number of threads over a one
inch length and not as the distance between the peaks of a thread like the metric system
An INCH thread will usually be followed by some initials like the example above. These initials describe the type and
the engineering standard for the thread. For the above example UNC stands for “Unified National Coarse” and BSW
stands for “British Standard Whitworth”. To an engineer, this classifies and defines the type of thread.