Posted by: woodbeecarver   in Tutorials



The RULE OF THUMB has since ancient time been a common form of measurement as well as an expression of speech. It is defined as a general or approximate principle, procedure or rule based on experience or practice. Carpenters often use thumb width or length from first knuckle to thumb tip as a quick and easy “one inch” measurement. The length of the thumb is approximately “three inches” or equal to the width of four fingers.

Often an artist will sight past an upright thumb at arms length to gain approximate perspective of a distant object. No one knows for sure who originated the “Rule of Thumb” but it has been suggested that Leonardo DaVinci used its principle in his study of human anatamony and artistic proportions.

Carvers can use the “Rule of Thumb” for a quick and approximate measurement while carving to visualize proportions, sight comparison measurements or one inch incremental measurement.

The Rule of Thumb falls into the category of “Baseball Measurement” which is simply “in the ball park” of close proximity. The accuracy in carving is more often the overall look rather

than a calipher measurement of exactness. Carvers should learn to carve for the “look” by relaxing the feeling of having to be tied to accurate measurement




Mickey Huston of River Valley Woodcarvers is a good carving friend who allowed himself to be photographed while demonstrating another way to apply the Rule of Thumb with the Rule of Three for Facial Proportions.

The Rule of Three of Facial Proportions divides the face into thirds:

hairline to eyebrow; eyebrow to bottom of nose; bottom of nose to bottom of chin  or face length is ‘three thirds long.’ The face is ‘two thirds’ wide when compared with face length.

Using the Rule of Thumb for facial proportions reveals that the face is three thumbs long and two thumbs wide. The point of this observation is simply to have a mental measurement of proportions and approximate comparison rather than actually laying a thumb against the facial areas. This is another way of visualizing the proportional divisions of the human face.

Another way to visualize this would be to study one’s own face in the mirror and use one’s own thumb to divide the three divisions of the face length and two divisions of the width. Next, instead of using the thumb, lay the four fingers of one’s hand flat against each of the three divisions to visualize the proportions. This thumb and hand exercise is simply to impress into the carver’s mind that the Rule of Three of Facial Proportions is a guide to be used while carving the human face in wood.

If the facial proportions are in the “ball park” then the carving will have a “look” of being accurate in the “eye of the beholder” resulting in a free flowing carved face with personality and character. In other words, it just looks right and looks tells it all.

Having the concept of the Rule of Three/Rule of Thumb fixed in the carver’s mind will set the carver free to carve the human face with the flare of creativity by not being constrained with thoughts of accurate measurements.

As a “Rule of Thumb” carving is an ever learning pursuit of happiness in the wonderful world of carving wood and making the best of friends through woodcarving.

 Carvers measure up.

This entry was posted on Saturday, May 14th, 2011 at 10:33 am and is filed under Tutorials. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.

Leave a reply

You must be logged in to post a comment.