The double-crank breast drill recently put on the market by the
Millers Falls Company, 74 Chambers street, New York, has some
special features in its construction which, it is said, add
considerably to the efficiency of this style of tool, making it
more powerful and durable.
Little description is necessary beyond calling attention to the
accompanying cut, which presents a general view of the drill.
The power is transmitted to the drill through very heavy cut
gears, which are speeded about two to one.
Double cranks, which are adjustable to any length, and by which
the speed and power may be regulated as desired, allow of both
hands being used simultaneously in the operation of the drill.
The breast-plate is 12 inches long, and curved to fit the shape
of the body, thus preventing the tool from swinging around when
in use.
The hole in the spindle which receives the drill is ½ inch in
diameter.
The same company provides Morse twist drills of all sizes, with
½ inch shank, to fit this machine. They also sell a special
chuck which will hold all round and square drills below inch in
diameter.
The special features referred to above in the construction of
this drill in which the improvement lies are the new form of the
breast-plate, together with the double handles for rotating the
drill.
By the use of such a broad breastplate the operator can apply
pressure to the drill with more convenience and comfort, because
of the greater surface presented to the body; its curved shape
also prevents the tool from rotating when in operation.
By the use of the two handles much greater power can be executed
on the drill, besides distributing the work to both arms.
The method of altering the lengths of the cranks to which the
handles are attached is shown in the cut. The two set-screws
near the crank axis allow the cranks to be set at any desired
length, as the quality of the work requires.
The tool throughout is finely finished, the standard of cast
iron being lacquered, and the cranks, arms and chuck
nickel-plated.
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