Why Won’t The Wood Fit?

Your wood fastening products seem to be built for yesteryear wood sizes. 2x’s are no longer larger than 1½”. Why can’t you manufacture these products with a little closer tolerance?

I received this question from a customer a few days ago via Ask Simpson, a web page where you can submit technical questions to our Engineering Department and we respond by e-mail. We have received similar variations of this question countless times over the years, so I thought it could use some discussion.

The National Design Specification for Wood Construction (NDS) Supplement Table 1A “Nominal and Minimum Dressed Sizes of Sawn Lumber” gives the minimum dry and green dimensions for sawn lumber. This specifies a nominal 2x, for example, as being 1½” dry and 1 9/16” green. NDS Supplement Section 3.1.1 defines dry lumber being seasoned to a moisture content of 19% or less, whereas green lumber is higher than 19%.

NDS Table 1A

NDS Table 1A

NDS 3.1.1

NDS 3.1.1

So what size do you make the connector?

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