PRECISION MEASURING AND GAGING - OD1642 - LESSON 1/TASK 2
time gradually tightening the turning handle screw (2).
Remove the gage
from the hole. Take measurements only once. Repeated attempts will produce
(14) Small Hole Gages.
Small hole gages (figure 13 on the following page)
are similar to telescoping gages.
They are smaller in size, adjustable,
having a rounded measuring member. A knurled screw in the end of the handle
is turned to expand the ball-shaped end in small holes and recesses.
micrometer is used to measure the ball end. Maximum measuring capacity is
1/2 inch. The set of four or more gages is used to check the dimensions of
small holes, slots, grooves and so forth from approximately 1/8 to 1/2 inch
(b) Uses. The small hole gages perform the same function as the
telescoping gages, except that they are used to transfer measurements in
smaller work. To use the small hole gages (figure 13, view B) fit the ball-
shaped point (1) into the hole or slot (2). Expand the ball-shaped end by
turning the screw (3) at the end of the handle. Use the same procedures in
taking measurements of the hole as explained in (13)(b) above for the
After the measurements have been made, use an outside
micrometer to gage the measurement.
(15) Snap Gages.
the nonadjustable and the adjustable.
(b) Nonadjustable Snap Gage. The nonadjustable type (figure 14 on
page 25) is of a solid construction, having two gaging members, GO (1) and
NO GO (2) as shown in figure 14. The part to be inspected is first tried on
the GO side and then the gage is reversed and the part is tried on the NO GO
side. Some solid snap gages (3) have combined gaging members in the same
set of jaws, known as a progressive snap gage. The outer member (4) gages
the GO dimension and the inner member (5) the NO GO dimension.