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User's Manual
DIAL INDICATOR
A dial indicator is used to measure shaft
run-out, shaft thrust, gear backlash, flywheel face run-out, flywheel
housing concentricity, and valve seat concentricity. You can mount a dial
indicator on a test stand or, with clamps and a magnetic base, directly on
the equipment to be measured. Figure 2-1 shows a typical dial indicator with
mounting accessories, Most dial indicators have components such as a bezel,
indicator pointer, tool post and clamp, magnetic tool holder, and sensor
button that are used in taking measurements.
The following procedures explain how to use
the indicator to take shaft run-out and crankshaft end play measurements.
Procedures for taking other measurements are similar.
Figure 2-1.�Typical dial indicator with
mounting accessories.
Shaft Runout
When you need to measure a shaft's runout,
select a suitable position on the shaft, free of keyways, corrosion, or
other damage. Clean the surface and remove any burrs around scratches or
dents. To take the runout measurement, use the following procedure:
1. Place the shaft in well-oiled V-blocks.
If the shaft is a crankshaft, place the bearing journals in the V-blocks.
2. Attach the magnetic base to a machined
surface. Mount the dial indicator on a tool mounting holder and attach the
holder to the base.
3. Adjust the mounting post so you can
easily read the face of the dial.
4. Move the indicator toward the shaft
until the sensor button just touches the surface you wish to measure.
5. Continue moving the indicator slowly
toward the shaft until the dial pointer has moved to the midpoint of its
travel on the dial face.
6. Leave the pointer at midtravel and turn
the bezel until the zero on the dial is aligned with the pointer.
7. You can now rotate and watch the pointer
to see if it moves. The total amount the pointer moves is called the total
indicator reading (TIR). If the shaft is straight, the pointer should remain
at zero.
Crankshaft End Play or Thrust Readings
To measure crankshaft end play or thrust,
use the following procedure:
1. Attach the dial indicator to a
convenient place near the vibration damper.
2. Position the dial indicator gauge so the
contact point touches the front of the vibration damper and moves the dial
indicator near the midpoint of its range.
3. Insert one end of a pry bar between a
main bearing cap and a crankshaft counterweight.
4. Move the crankshaft toward the dial
indicator. Be sure to maintain a constant pressure on the prybar.
5. Set the dial indicator to zero.
6. Remove the prybar and then reinsert it
on the other side of the main bearing cap.
7. Carefully pry the crankshaft in the
opposite direction to measure the crankshaft end play. Repeat your
measurement a minimum of two times for accuracy.
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