The theory and construction of a sector is covered in both our books, though in the softcover “By Hound and Eye” we provide a workable sector on the last page (which you cut out with a pair of scissors.) If you have a two-or three-ft. folding rule you can use that as a sector as well. In this post I’ll show you how to use this traditional layout tool for one of the most basic–not to mention useful–purposes: to lay out an even spacing of fasteners along a line. In addition to a sector (this is the paper one from the book), you’ll need a pair of dividers and a sharp awl for enlarging the divider’s pin-pricks to guide your drill bit. Now decide how many fasteners you want (I’m showing an over-kill amount for illustration purposes).
Begin by drawing a location line for the fasteners and then establish the location of the first and last fastener. As a general rule, I step in at least twice the thickness of the material being fastened–a strategy that reduces the chance of the fasteners near the edge splitting out the grain.
Now decide how many fasteners you want to fall between the first and last. In this example I picked eight–which means there will be nine gaps. So open up the legs of the sector and orient the first and last location points with “9” on each leg.
Set the dividers to the spread of the “1” s on the legs. This is–by the magic of geometry–the spacing of the fasteners. (Note that we are not accounting for the width of the fastener heads to get exact spacing–you can only be so anal about such things).
Starting with the first fastener position, step out along the line until you reach the last position. If you are lucky, you won’t need to make any adjustment. If you come up short or long, adjust accordingly–but make only a minute adjustment as it will be multiplied by nine steps.
And there you have it…ten evenly spaced fasteners without a measurement anywhere in sight!