TABLE OF CONTENTS Almost all of the tools in this book can be operated successfully in fully mechanized machines, in manual machines and in portable drills. Many also can be used successfully as hand tools. Whether a tool is particularly applicable or not in one of these categories will be discussed in this chapter.
Every manufacturer suggests that safety glasses should be used when performing any chip-producing operation. While countersinks may not throw as many chips as drilling or milling, it only takes one chip to destroy an eye. Wear safety glasses whenever countersinking.
It is also important to make sure that countersink tools are centered in their holders so when power is applied that they do not come loose because the chuck jaws are not holding them correctly. Remove chuck keys before turning on power when chuck jaws are used.
Countersinks have been produced with at least 11 "standard" shanks. They include in approximate order of introduction:
Pyramidal square shank (pre-1900)
Straight shank tang-ended
Morse taper tang-end shank (1900-1950)
Simple round shank
Weldon shank
Threaded shank
Radial drive shank
Pin drive shank
Stub taper shank
Quick change detent shank
Hex shank tools
The pyramidal square shank (Fig. 5-1) has been used since at least 1 AD and it lasted well into the 1900s (Anonymous 1880). Patents show that the round shank began appearing around the 1900s and was probably used for dental use in the mid 1800s. The tang-ended Morse taper shank (Fig. 5-2 top) was produced prior to...
