This section is from the book "Spons' Mechanics' Own Book: A Manual For Handicraftsmen And Amateurs", by Edward Spon. Also available from Amazon: Spons' Mechanics' Own Book.
This very useful adjunct to the brace and bits is shown in Fig. 399. Its object is to alter the direction of the pressure in boring (so as to permit boring in a corner), for which purpose it is placed between the brace and bit, forming their connecting link. The angle at which the hole is to be bored is decided beforehand, and the stock is properly set, the ball joint enabling the tool to turn without hindrance. It is sold by Churchills for 8s. 6d.