Secrets of the Sector

Just 2 sticks and 1 hinge will eliminate both math and errors from your layout work.

By Jim Tolpin
Pages:40-45

From the June 2011 issue #190
Buy this issue now

If you haven’t heard of the sector, it probably means you aren’t an artisan or a ship’s navigator living and working
in the 17th and 18th centuries.

An invention attributed to Galileo, the sector is a calculation instrument comprised of a pair of hinged sticks
engraved with a variety of scales that – coupled with a pair of dividers – enabled you to solve trigonometry, division and multiplication problems (amongst other functions).

Video: Watch a sector in use in the shop.
Web site: Visit the Port Townsend School of Woodworking’s web site.
To buy: “The New Traditional Woodworker” by Jim Tolpin.
In our store: “Measure Twice, Cut Once” by Jim Tolpin.

From the June 2011 issue #190
Buy this issue now