How to decode the leaf chain part number system

Leaf chain part numbers are not arbitrary things.

The different combinations of letters and numbers that make up a leaf chain part number provide you with vital information about the type of chain, its pitch and its lacing.

This blog post provides an explanation of these three key elements to enable you to quickly and accurately select the correct chain for your materials handling application.

Once you know what to look for, you’ll see how easy it is to decode any leaf chain part number in an instant.

Leaf chain series

The first two letters in the leaf chain part number refer to the leaf chain series – for example, AL, EL-LL and BL-LH series leaf chains:

  • AL series (American Light) chain is a lightweight chain used for light-load lifting applications and machine tools. It is constructed from American standard roller chain components and is manufactured to the ANSI B29.9 standard.
  • EL-LL series (European Light – Leaf Light) chain is manufactured according to ISO4347, DIN8152 and NFE26107 standards. EL-LL series chain shares many similarities with AL series chain – it is lightweight, it is constructed from roller chain components and it is used for machine tools and light load lifting applications. The key difference however is that it’s manufactured to the European standard.
  • BL-LH series (Leaf Heavy) chain is heavier duty chain than AL and EL-LL series and is the only leaf chain that is constructed from specific leaf chain components. It is also the most common chain used for forklift trucks, lifting and materials handling equipment. BL-LH series leaf chain is manufactured in compliance with ISO4347, DIN8152, ANSI B29.8 and NFE26107.

Leaf chain pitch

The pitch of a chain is the average distance between pins.

The first one or two digits (depending on whether the leaf chain part number has three of four digits) refer to the pitch of the chain.

These digits will vary according to the series of the chain.

  • AL series chain is measured in eighths of an inch – but  only the numerator of the fraction is given. For example, ‘4’ represents 4/8” which can be reduced to ½” and ’10’ represents 10/8” which can be reduced to 1 ¼”.
  • EL-LL and BL-LL series chain is measured in both eighths and sixteenths of an inch. For example, BL12 represents 12/8” and LL24 represents 24/16” – both of which can be reduced to 1 ½”.

To calculate the metric pitch it’s then simply a case of dividing the numerator by the denominator and multiplying by 25.4 (as 1 inch is equal to 25.4 mm.)

Leaf chain lacing

Lacing refers to a leaf chain’s plate structure.

The chain lacing can be determined by looking at the final two digits of the part number.

The last number provides information about the number of inner plates, while the second-to-last number refers to the number of outer plates and intermediate plates (there are only ever two outer plates).

Leaf chain part numbers in practice

Now let’s take a closer look at some specific leaf chain part numbers:

Leaf chain part number: AL1066

From this part number, we can tell that:

  • this is a lightweight American standard chain made from roller chain components.
  • the pitch is 10/8” which can be expressed as 1 ¼” or 31.75mm.
  • the chain is constructed from six inner plates, four intermediate plates and two outer plates.

Leaf chain part number: EL544-LL1044

From this part number, we can instantly see that:

  • this a lightweight European standard chain made from roller chain components.
  • the pitch is 5/8” or 10/16” which can also be expressed as 15.875mm.
  • it is constructed from four inner plates, two intermediate plates and two outer plates.

Leaf chain part number BL623-LH1223

From this part number, we can determine that:

  • this is a sturdy chain made from specific leaf chain components.
  • the pitch is 6/8” or 12/16” which can be expressed as ¾” or 19.05mm.
  • the chain is constructed from three inner plates and two outer plates.

Selecting the correct leaf chain for your specific application is of vital importance for safety, optimum performance of your materials handling equipment and longer chain life. 

Being able to quickly and easily decode the leaf chain part number system will ensure you choose the right product for the most demanding of applications.

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