Starrett 64381, User Manual

Page: 8 / 64

8 PKG08804-UM128
ENGLISH
128 WITH MICROMETER HEAD ONLY
The desired range is obtained by using the extension rods
and rod points with the 2" (50mm) range micrometer
head (see Table 1). The necessary combination of rods
with the micrometer head are joined together by threaded
connections. They are brought to seat on hardened and
lapped faces with a firm, but not extreme amount of
pressure, to assure the accuracy of the seating.
Caution : A high degree of cleanliness must be
maintained between all mastering or mating faces
of end rods, extension rods, contact nibs, etc., when
performing adjustments, settings of calibration, in order
to preserve the measurement integrity of the system.
When the line of measurement is not predetermined,
the correct procedure in measuring with the inside
micrometer is to hold the non-micrometer head end in
contact with the piece to be measured. Then use the
micrometer head to sweep the other end of the surface
to be gaged to determine the point for final reading.
When the tool is used in a horizontal position, it should
be supported the full length by positioning the collars
in "V" grooves.
In maintaining the micrometer head accuracy, care in
handling and an occasional drop of light instrument
oil on the threads is sufficient. Adjustment for thread
wear is provided in a binding nut which is exposed
by backing off the thimble. Adjustment of individual
rods allow for wear of contact ends. A light coating
of preservative should be kept on the rods when not
in use. Repair of the tool should be undertaken by
qualified personnel or returned to the factory.