Metric and imperial timing belts – what is the difference?

Metric and imperial timing belts – what is the difference?

I regularly notice that our customers find it difficult to determine the correct type of timing belt. In this blog, I will attempt to break down the basic differences of size and structure. Timing belts are available in two measurements: metric (mm) and imperial (inch).

This is only a difference in measurement and not in the actual size of the belt.

Tooth shapes of a timing belt

There are a variety of tooth shapes to choose from. The size or tooth shape can make an important difference in application. The most common shapes are the trapezoid and the round shape. The trapezoid shape is used in standard applications, such as for transporting products and in packaging lines. The round shape is mainly used in elevator systems, for accurate positioning and lifting.

For the metric measurement we have the following types with trapezoid-shaped teeth:

• T5, AT5
• T10, AT10
• T20, AT20

The metric measurement also has a model with a round tooth shape, such as:

• HTD (5M)
• HTD (8M)
• HTD (14M)

In the imperial measurement only a trapezoid tooth shape is available:
• L
• H
• XL
• XH

Reading measurements

It can be difficult to know how to read different measurement symbols. With metric timing belts the figure in the description indicates the tooth pitch. With imperial types this is different: L = 3/8” (9.525 mm), H = 1/2” (12.7 mm), XL = 0.2” (5.08 mm) and the XH = 7/8” (22.225 mm). The letter A has also been added in some metric measurements. (AT5, AT10 and AT20). These types have trapezoid shaped teeth, but the tooth base is larger so that the teeth can be loaded for heavier displacement.

HabaSYNC timing belts

We have developed a gadget to help you determine the correct timing belt type. We make this Pitch Guide available for free. Are you interested in a HabaSYNC Pitch Guide? Send your contact data to:

2017 June 1  |  Posted by

René Grevengoed

René Grevengoed is an Application Engineer who has worked at Habasit in the Netherlands since 1996. He speaks native Dutch and he is also fluent in English. Grevengoed specializes in general conveying, including fabric conveyor and power transmission belts. His expertise is applicable in several industries, including food, material handling, as well as printing and paper applications. Grevengoed’s experience began in workshops and onsite fittings where he was able to acquire the necessary special skills in order to progress to where he is today.

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