Fig. 20.
A fast cutting cross-cut saw should have deep teeth.
Much useful information on saws can be obtained from a small book published and issued by Disston & Sons, Philadelphia, entitled “Hand Book for Lumbermen,” which, I believe, can be obtained on application.
The other tools used in this course will be taken up in order as they are used in the work.
EXERCISE NO. 1.
The following operations are designed to give the student a training in the use and care of the most commonly used carpenters’ and joiners’ tools. It is not intended that the student will be able to finish each exercise in one trial, as mistakes will be very common at the beginning, and it is advised that at least two or three trials may be given for the practice and training involved.
In [Fig. 21] is shown the working drawing (mechanical drawing) of a rectangular block of wood, and before we proceed to do the work required to finish this, we will study the drawing.
In order to represent solid figures with their three dimensions, length, breadth, and thickness, on a plane surface, i.e., a sheet of paper, we must have at least two drawings (projections), but to simplify the reading still further a third drawing is given, sometimes with additional drawings in the form of cross-sections.
To understand fully the principle upon which a working drawing is made, we will suppose that two transparent planes cross each other at right angles, making four right angles as shown in [Fig. 22], (these angles to be known as the 1st, 2nd, 3rd, and 4th angle of the co-ordinate planes), and respectively called the Horizontal and the Vertical planes.