A short time ago Lee Sell, was doing some research on Lufkin boxwood rules and discovered that all of Lufkin's 24-inch four-fold rules with the number "1" as the last digit of the model number were one inch wide. This intrigued him to further his research to see if the rest of the digits also represented some characteristics of the rule. The chart below will demonstrate what he has determined to be Lufkin 's numbering system of all of the 2-, 3-, and 4-foot four-fold rules.

The Lufkin Numbering System of Boxwood Rules

by Lee Sell

1st Digit / Type of Joint 2nd Digit / Type of Edge 3rd Digit / Width of Rule
6 / Round Joint 5 / Unbound - Middle Plates 0 = 3/4 inch
7 / Square Joint 6 / Unbound Edge Plates 1 = 1 inch
8 / Arch Joint 7 / One half Bound 2 = 1 3/8 inch
9 / Dbl. Arch Joint 8 / Fully Bound 3 = 1 1/2 inch

All the 2-foot rules have three digits. The 3-and 4-foot rules have four digits. The difference between the 2-foot rules and the 3-and 4-foot rules is that in the 3-and 4-foot rules, the first digit represents the length of the rule. Then the 2nd, 3rd, and 4th, digits represents the description of the rule as I have outlined in the chart above. An example is the No. 3751 rule, which is 36 inches long, has a square joint, is unbound with middle plates, and is 1 inch wide.

Two exceptions to this theory are the two digit No. 48 and No. 49 rules which are of more recent vintage. Another change came about shortly after W. W .11 when most rules were discontinued. Lufkin's No. 3851 plus a few more continued to be produced for a short time. The No. 3851, which had an arch joint, was changed to a square joint. This was probably a matter of economics. The square joint was easier to manufacture than the arch joint. Also, as there were so few rules in production at this time that the numbers were not so important in the description of the rule.

At the present time, I cannot decipher the system used for the rest of the Lufkin rules. Most of them are specialty types such as caliper rules, 3 fold, 2 fold, or no fold. I welcome any input or ideas on this subject.

-Lee lives in Modesto, CA. He collects miscellaneous measuring devices and specializes in Lufkin tapes and rules. Call him at 209-545-3130 or E-mail: ssell@ainet.com