PRECISION MEASURING AND GAGING - OD1642 - LESSON 1/TASK 2
SURFACE GAGE/SURFACE PLATE.
(12) Toolmaker's Buttons.
Toolmaker's buttons (figure 11 on the
following page) are hardened and ground cylindrical pieces of steel, used to
locate the centers of holes with extreme accuracy. As many buttons may be
used as necessary on the same layout by spacing them the proper distance
(13) Telescoping Gages.
(a) General. Telescoping gages (figure 12 on the following page)
are used to gage large holes and to measure inside distances. These gages
are equipped with a plunger (1) that can be locked in the measuring position
by a knurled screw or locking nut (2) in the end of the handle (3). Maximum
measuring capacity is 6 inches. Measurements must be calipered on the gage
by a micrometer, as in the case of the small hole gages. They are also used
when measurements cannot be taken with a standard micrometer. Telescoping
gages are particularly adaptable for roughly bored work and odd sizes and
shapes of holes.