What Does the Stamp on a Block and Tackle Window Balance Mean

Posted by Window Hardware Direct on

The stamp on a block and tackle window balance is a key identifying feature on each balance. The numbers on the stamp will tell you the balance series, the balance length and the balance weight range. Continue reading to learn how you can determine the correct replacement window balance you need.

Block and Tackle Balance Stamp

Location of the stamp on a block and tackle balance

Determining the Series

To determine what series balance you have, you need to look at how the stamp is placed on the balance. If the stamp is laser printed onto the balance, that is most likely our 300 Series Balance, if it is engraved, then that is most likely our 400 Series Balance. There could be other series associated with these styles of stamps, but those are the most common. 

Determining Length

One of the most important dimensions for your balance is the length and that can be determined pretty simply from your balance. Your stamp will either have the form XX-X or XXXX (e.g. 14-4 or 1440). The first two numbers will determine the length of the balance. This number is one inch shorter than the actual length of your balance, for example, if your balance is stamped 14-4 or 1440 your balance length is 15". Please note: If your balance does not measure an exact length, please contact us before placing your order (e.g. 15-5/8")

Determining Weight

Another important dimension you need for your balance is the weight lifting capacity the balance will hold. The weight capacity can be determined from the balance, but not directly. You will have to compare your stamp to others that are available. For example, if your stamp is 14-4 or 1440, you would use the number after the dash or the 40 to get the correct weight range.

That is the basics of stamps on block and tackle window balances. There are many different balances with many different stamps. If you have a balance and you need help determining the correct replacement part, give us a call at 1-800-842-0974, contact us, or chat with us and we will be happy to assist you. 

Watch the video below to learn more: 

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  • The sash balance is 31" long, 9/16" in depth and 5/8" width, but I don’t know the lifting weight. The balance is not stamped due to the age. Will I be able to get the right replacement from WHD?

  • Hi, I need to replace the Block and Tackle lifts in some windows. I am having trouble figuring out what is needed. I do know they are 30inches long 5/8 in wide and 9/16 in deep. That might be enough information, but I am not sure of the lifting weight.
    The I/D 29B Y is stamped into the metal on the back. Can you direct me to a suitable replacement. Thanks for your help. Terry Chaires

    Terry Chaires on

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