(D) Bushing not Cleaned Well Before
Measurement — If the bushing surface is
not cleaned the measurement taken will be
oversized.
(E) Calipers Not Placed at Most Worn
Portion of Bushing — If the caliper
is located inboard or outboard of the
minimum diameter along its length in a
given wear position the reading will be
undersized.
PRACTICE!
The best way to practice measuring
bushing wear is with bushings removed
from the track. You should be able to
repeat the measurements made by yourself
and others with an accuracy of ±.01"
(± 0.25 mm).
2. Depth Gauge Method
The method for measuring the vertical
position of bushings uses the same depth
gauge used for links. This method is more
free of the measurement technique errors
encountered with the caliper, but may be
subject to slight track link dimensional dif-
ferences and track shoe bending. It is also
subject to the same technique errors as
link height measurements. These include:
(a) parts not cleaned, (b) depth gauge base
not positioned correctly with respect to
bushing length and (c) depth gauge probe
not forming a perpendicular or 90° angle
with the shoe.
Disadvantages of the depth gauge
method
(A) Cannot determine reverse or forward
drive side wear, which is critical in
most applications.
37
General Information
SEALED & LUBRICATED TRACK PINS & BUSHINGS