Paragraph 11. It is quite frequently necessary to bore holes perpendicularly into a piece of material. To do this it is necessary to hold the bit constantly at a right angle to the material in every direction. To be sure that you are doing so, it is well to have the try-square handy, and when you start the bit, test the position by holding the try-square as shown in Figure 28. You should also test frequently with the try-square while boring the hole.

Figure 28.