A folding ruler, also known as a carpenter's ruler or mason's ruler, folds or otherwise collapses, so that it is generally between six and eight inches long when folded, and can be kept in a pocket. Carpenter's overalls typically have a special pocket on the side of a leg to hold one of these rulers. (Carpenter's overalls sold today may advertise this pocket as also suitable for holding a cell phone.) Folding rulers have been largely replaced by tape measures, but 'zig-zag' rulers are still being manufactured.
Folding rulers have a long history. A (Roman) foot-long folding ruler made of brass was found in the ruins of Pompeii. Folding rulers are known from Italy by the end of the 16th century. Most folding rulers were made from wood, particularly boxwood. Some were made of ivory or bone, while many are now made of metal or man-made materials. Hinges, swivel joints, and bandings were usually made of brass or 'German silver' (a copper and nickle alloy).
The Tison Tool Tool barn collection includes about 20 folding rulers. The five rulers covered in this post are all made of boxwood and brass, and all include a caliper for measuring the outside diameter or width on an object. The first three are two-fold, and are one foot long when opened. The caliper on these three rulers each have a bar just over five inches long, which would allow measurement of objects up to about four inches in diameter.
First is this folding ruler, a model No. 36-1/2 made by the Stanley Tool and Level Company.
This next folding ruler doe not have a manufacturer's mark on it, but it is labeled as a model No. 36-1/2, and was probably made by Stanley.
This next folding ruler is also a one-foot two-fold ruler, a Stanley model 36-1/2 R. (Stanley also made a model 36-1/2 L folding ruler, but the Tison Tool Barn does not have an example of that model.) I am not aware of how this ruler (model 36-1/2 R) differs from the plain model 36-1/2.
The next folding ruler in the Tison Tool Barn is a Lufkin model No. 386, made of boxwood and brass. It is also one foot long when opened, but is four-fold, meaning that is is only about 3-1/4 inches long when folded. This ruler also has a caliper, but the bar is only three inches long.
The last item in this post is not a folding ruler, but at just four inches long, does count as a pocket ruler. It is a Stanley model No. 136 R, and includes a caliper.
In my next post I will look at some two-foot long folding rulers from the Tison Tool Barn collection.
I have been a volunteer at the Matheson History Museum. Feeling an affinity with old hand tools (some of which I remember from my youth), I have tried to learn more about the history of the tools in the Tison Tool Barn, and how they were used.
All text and photographs by Donald Albury in this blog are licensed under a Creative Commons Attribution-ShareAlike 4.0 International License. All illustrations taken from Wikimedia Commons are either in the public domain, or have been released under a Creative Commons license.
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