Understanding the Different Weights of Binding Cover Stocks

Our sales staff at MyBinding.com are commonly asked about the thicknesses of the binding covers that we carry on our site. Unfortunately, understanding the way that cover stocks are measured can be somewhat tricky since several different measuring standards are used. This article is designed to give you a quick overview of the different measuring standards used for the cover stocks that we carry.

• Most of the clear binding covers and poly binding covers available from MyBinding.com are measured in Mil’s (also sometimes referred to as gauge). At first glance, it might appear that this is a measurement in millimeters. However, one mil actually equals 0.001 inch. Thus a 10mil clear cover has a caliper measurement of 0.010 inches and a 19mil poly cover has a caliper measurement of 0.019 inches.
• The regency composition / leatherette covers that we carry are measured in points rather than mils. For instance, most of the regency composition / leatherette covers that we carry are rated as 17pt covers. Each point is equal to 0.001 inches (the same as mil’s or gauge). Thus the 17pt covers that we carry have a caliper measurement of approximately 0.017 inches.
• Most of the paper covers that we carry are measured in weights. For instance, GBC’s linen weave paper covers are made from 80lb cover stock. This measurement is the actual weight of 500 master sheets (25” x 38” in size for cover stocks). Depending on the type of paper you are using the weight is based on different master sheet sizes making it very difficult to compare weights of bond paper with offset paper or index stock with cover stock. However, to give you an idea, 80lb cover stock is approximately equivalent to 9.5 Mils, 90lb cover stock is approximately equivalent to 10 Mils and 100lb cover stock is approximately equivalent to 11 Mils.

We know that this can all be a little bit confusing but to help you compare apples to apples, here is a quick reference chart that shows several of the different types of paper and their approximate equivalents.

Paper Weights Table

If you have any other questions or comments about this article please feel free to
email us at sales@mybinding.com or call us at 1-800-944-4573

Written Jeff McRitchie
©2007 www.MyBinding.com