A Daisy wheel is a Module

Andrea Palladio wrote that he chose to use a Module to lay out the columns he drew.*
 

All the dimensions which he noted were derived from the diameter
 of the column measured at the bottom,  ie: the height of the column, the capital, architrave, frieze and cornice.

He wrote, " ..in the dividing and measuring the said orders, I would not make use of any certain and determinate measure peculiar to any city, as a cubit, foot, or palm, knowing that these several measures differ as much as the cities and countries; but imitating Vitruvius, who divides the Doric order with a measure taken from the thickness or diameter of the columns, common to all, and by him called a module, I shall make use of the same measure in all the orders." 

 

 

 

The cross section, the diameter, of a column is a circle.

 

 

 

 

A daisy wheel is a circle.

It's easy to draw with a compass or dividers.

 

 

 

 

 

 

 

 

It is a module.

 

 

 

This sheathing board leans against my corn crib. It was siding for a timber framed shed, part of a farm complex in Danby, Vermont. The board is 10' tall, angled at the top to fit under the roof eaves. 

 

 

Today it folds in 2 places. It fits in my car; it stands on its own at a conference, ready to be seen and examined.

 

 

The daisy wheel was cut into the board at a height of 42"  above the floor, a good height for the builder and his crew who would have set their dividers to its width. All of them needed to be using the exact same dimension (their module) as they laid out their work.  

 

This daisy wheel's diameter is slightly more than 8 inches.

The wheel is just above the center of the photo. In the images below the board has been laid down. 

 

 

Dividers set from one petal to the other across from it, the diameter of the daisy wheel.

Note the holes on the circumference and the center left by previous users.

 

 

 

Here the dividers, set open at the same angle, are rotated 60* farther around the circumference. They are at the points of another pair of daisy wheel petals, the circle's diameter. The distance is the same as it was before. 

Note the holes are not quite on the petals tips, rather they are on the circumference of the circle. Many daisy wheels were not precise.  

 

 

 

Here the dividers points have been slipped into the holes drilled by all the previous carpenters' dividers.

 

My dividers slid right in place, so secure they stood by themselves.

I had never tried this before - I was surprised and awed: my placement was one that many had done before me. 

 

The black marks on the board above the daisy wheel are the holes left by rusty nails.

 

* Andrea Palladio, Four Books on Architecture, 1570, Isaac Ware English Translation, 1738, Dover reprint, 1965. Palladio's statement about modules is on page 13, First Book. The image of the Doric Order is Plate XII, First Book.