Wing-nut. An iron nut having a wing at each side. Sometimes called a “butterfly nut.”
Yoke. A branch pipe, or a two-way coupling for pipes, particularly twin hot and cold-water pipes that unite in their discharge.
Y.—A pipe fitting for uniting two pipes at an angle of 45°.
HISTORICAL INTRODUCTION.
Gourd, Cauldron and Pipkin.
The very small degree of antiquity to which machine tools can lay claim appears forcibly in the sparse records of the state of the mechanic arts a century ago.
A few tools of a rude kind, such as trip-hammers (worked by water wheels), and a few special ones, which aimed at accuracy but were of limited application, such as “mills” for boring cannon, or “engines” for cutting the teeth of clock wheels, were almost their only representatives.