Tc 9-524 fundamentals of machine tools

TAP AND DIE WORK
Hand tapping and hand die work can be done on a drilling
machine. The drill chuck is used to align the tap or die.
DRILL HOLDING DEVICES
The revolving vertical spindle of the drilling machine holds
and drives the cutting tool. In order to use various sizes and
shapes of drills in various machines three types of drill
holding devices, which fit the spindle of the drilling machines,
are used: the geared drill chuck, the drill sleeve, and the drill
socket (Figure 4-22). The larger drilling machines have a
spindle that has a standard Morse taper at the bottom
end. There are three types of drill holding devices: the geared
drill chuck, the drill sleeve, and the drill socket.
GEARED DRILL CHUCKS
Drills with straight shanks are held in geared drill chucks
which have three adjustable jaws to clamp onto the drill.
Smaller size drills are made with straight shanks because of
the extra cost of providing these sizes if tapered. Geared drill
chucks come in various sizes, with the 3/8 or 1/2-inch
capacity chuck being the most common. The shank of the
chuck is set into the spindle of the drilling machine by
inserting the chuck’s shank into the spindle’s internal taper
and seating the shank into the taper with a light blow with a
soft hammer. Both the internal and external taper surfaces
must be clean and free of chips for the shank to seat and lock
properly. The drill is locked into the chuck by using the
chuck key to simultaneously tighten the three chuck jaws.
Geared drill chucks can also come with a morse tapered
shank and may have a different method of attaching They
may screw on, have a Jarno taper, or a Jacob’s back taper.
DRILL SOCKETS AND DRILL SLEEVES
Morse taper shank drills come in several sizes, thus, adapters
must be used for mounting them into various drilling machine
spindles. Drill sleeves and drill sockets are designed to add to
or subtract from the Morse taper for fitting a drill into the
chuck spindle. For example, it is common for a 3/4 inch twist