Simple measuring tools, such as dividers, calipers, and compasses, make it easy to keep carvings in proportion.

Simple measuring tools, such as dividers, calipers, and compasses, make it easy to keep carvings in proportion.

Get Started Carving / Tools for Beginners

Using Compasses, Calipers, and Dividers

Transfer measurements and maintain proportions with these simple tools

by Bob Duncan


This article was first published in issue 57 of Woodcarving Illustrated.


Basic measuring tools have been around for most of documented history; the Freemasons include dividers in their symbol. These simple tools help carvers create symmetry and transfer measurements from a study cast or clay model.

If you break them down to their simplest forms, dividers, calipers, and compasses are similar—two pieces of material joined at a pivoting axis on one end.

Dividers and Calipers

Dividers are the most simple of the three tools because they feature two identical straight legs, which usually end in a point. There are many shapes of calipers, but the most useful calipers for woodcarvers have two curving legs that come together at the end.

Dividers and calipers are useful for gauging proportions while carving. Artists say that a face is about five eyes wide and there is one eye-width
of space between the eyes. While you can use a ruler to measure the width of an eye, it’s quicker, easier, and more accurate to set a pair of dividers or calipers to the width of an eye and use the dividers to make the marks.

Use dividers to transfer measurements from clay models, patterns, or study sticks to your carving.

You can also use dividers or calipers to help position elements on the face. After you carve an iris, for example, place one leg of the dividers in the outside corner of the eye and place the other leg of the dividers on the inside edge of the iris. Transfer that width to the other eye to place the second iris in the correct position.

Dividers or calipers are also useful for transferring dimensions from a clay model to your blank, especially if you make a full-sized clay model. Use the calipers or dividers to transfer the locations of landmarks from the model to the carving. Some types of calipers allow you to increase the proportions as you transfer the measurements. These specialized tools, called proportion calipers, allow you to make a half-size model and scale up the dimensions while transferring them to the carving.

Another great way to use calipers is to ensure elements on both sides of a carving, such as arms and legs, are the same size. I prefer calipers for this use, because the curved legs fit around elements easier.

Simple Shopmade Calipers

Carver, author, and instructor Rick Jensen creates his own calipers from the wooden paint stirring sticks hardware stores give away when you buy paint. Rick shapes the lower part of each stick into a graceful curve that ends in a point. He drills a hole in the other end, threads a machine screw through the hole, and locks the screw in place with a wing nut. While a caliper like this probably isn’t accurate to the thousands of an inch, it is more than accurate enough for a carving.

Compasses

Like dividers, a compass has two straight legs; however, one leg holds a pencil or other writing implement. A compass is often used to draw circles, which are common in geometric carvings and chip carvings. A compass is useful to mark regular distances, such as the points on a geometric chip carving. I also use a compass to mark the depths of the different layers in a relief carving.

Although you can buy precision engineered calipers, dividers, and compasses with hardened steel tips, you really don’t need that sort of accuracy when it comes to carving. You can pick up a functional compass at an office supply store. Wherever you find them, these inexpensive measuring tools are useful additions to your carving tool kit.


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