Using The 6V6000 Dial Bore Gauge Group{0761} Caterpillar

The 6V6000 Dial Bore Gauge Group permits measurements to be taken in diameter ranges of 30.0 to 50.8 mm (1.181 to 2.000"). The gauge has a depth range of 8.5 to 150 mm (.33 to 5.9") and is marked in intervals of .002 mm (.00008").

Components Of The 6V6000 Dial Bore Gauge Group

1. Dial Bore Gauge

2. Gauge Points With Lock Nuts

3. Indicating Finger Clamp

4. Ball Tool

5. Quick Setting Wrench

6. Hex Wrenches

7. Storage Box

Setting The Dial Bore Gauge

(1) The following procedure shows how to set dial bore gauge (1) using quick-setting wrench (2) and setting fixture (3). Quick-setting wrench (2) should not be used as a setting standard. However, the wrench does give a means of presetting the gauge to within approximately 0.05 mm (.002") of the standard size. The wrench also makes it easier to adjust the gauge points.

(2) Before setting the gauge, learn the following characteristics of quick setting wrench (2) and the gauge point and lock nut assembly on dial bore gauge (1).

(3) The lock nut drive slot in wrench (2) has been machined off center so there is a small lug (A) and large lug (B). The gauge point drive slot has also been machined this way to make small lug (C) and large lug (D). Large lug (B) is also in alignment with micrometer scale (E) on the wrench.

(4) On the gauge point and lock nut assembly, the flats on both the lock nut and the end of the gauge point have been machined off center. This makes large flat (F) and small flat (G) on the gauge point and large flat (H) and small flat (J) on the lock nut. IMPORTANT: The lock nut must always be installed with large chamfer (K) toward the gauge head.

(5) Find the correct gauge point using the table below. For example, if the bore to be measured has a diameter of 34.4 mm (1.3543"), the gauge point from vial no. 1 should be used.

NOTE: Although the gauge point in vial no. 4 has a range up to 50.8 mm (2.0000"), the setting fixture can only be calibrated to 50.0 mm (1.9685").

(6) Install the gauge point in dial bore gauge (1) as follows:

a) Slide adjusting knob (4) all the way out to the maximum open position. Hold wrench (2) so the micrometer scale is up as shown. With large flat (H) of lock nut (5) up, put gauge point (6) in position in wrench (2).

b) Slide adjusting knob (4) inward while turning it slowly until the drive slot in the wrench engages flats (F) and (G) of the gauge point. Hold the wrench at a small angle, with gauge point (6) upward. Turn gauge point (6) into dial bore gauge (1) until lock nut (5) comes in contact with the head of the dial bore gauge. Do not tighten the lock nut.

c) While holding lock nut (5) in this position, turn adjusting knob (4) to the desired setting. Keep a light inward pressure on knob (4) while making this setting. Always come to the final setting while turning knob (4) clockwise [as seen from same end of wrench as knob (4)].

d) Tighten lock nut (5) by turning locking knob (7) and adjusting knob (4) at the same time while keeping just enough tension on the adjusting knob to hold the micrometer setting.

NOTE: After the final calibration of the dial bore gauge, the "0" point of the indicator hand may not be in the most desired reading position. To change this position, put wrench (2) on the gauge point and look at the micrometer reading. Loosen lock nut (5) and turn adjusting knob (4) until the micrometer reading changes the same amount as the indicator hand is to be moved.

(7) Use nest (8) from the 6V6030 Setting Fixture Group to calibrate the 6V6000 Dial Bore Gauge. Nest (8) has a diameter range of 30.0 to 50.8 mm (1.181" to 2.000"). Put nest (8) in position on the setting fixture group as shown. Make sure the spindle lock is not engaged. Turn micrometer spindle (9) counterclockwise to a point approximately 0.5 mm (0.020") more than the size being set.

(8) Carefully put gauge (1) in nest (8) with the gauge point toward the micrometer spindle and keyway (10) in alignment with key (11) in the nest. Turn spindle (9) in toward the gauge until the micrometer reads the exact size being set. Tighten the spindle lock. The spindle should now be in contact with the gauge point. IMPORTANT: Always set the micrometer by turning the spindle toward the gauge. If the spindle is turned in past the desired setting, turn the spindle out and then back in again to the correct setting.

(9) Twist nest (8) in the horizontal plane until indicator hand (12) shows the minimum or "most minus (-)" reading. The indicator hand should be within approximately 30° of the 12 o'clock position on the dial. If it is not, use the quick setting wrench to adjust the position of the gauge point as shown in step 6 on page 7.

(10) If the indicator hand is within 30° of the 12 o'clock position, loosen screw (13) and move the dial so the zero on the scale is in alignment with the indicator hand. Tighten screw (13). Check to make sure the gauge has not moved during this setting. If the gauge has not moved, it is now set to size. If the gauge has moved, again follow steps 9 and 10.

Adjusting The Centralizer Points

For maximum accuracy, the centralizer points must be in firm contact with the wall of the bore being measured. Use the following procedure to adjust the centralizer points.

(1) Put the 3/32" hex wrench (1) into the socket of the centralizer adjusting cam (2). Turn the wrench and cam until centralizer points (3) are fully retracted. With the wrench in the socket, put the gauge head approximately 9 mm (.35") into the bore being measured.

(2) With the gauge in a vertical position as shown, turn centralizer adjusting cam (2) until the centralizer points are firmly in contact with the wall of the bore.

NOTE: To retract the centralizer points and indicating finger (4), push in on retractor lever (5).

Adjusting Worn Centralizer Points

(1) When centralizer points (1) become worn, they must be adjusted to keep accuracy. Always adjust both points at the same time. Do this by putting the long leg of 3/32" hex wrench (2) through both centralizer points, and turning both points at the same time until new wear surfaces are in contact with the wall of the bore.

Changing The Position Of The Indicator

(1) If necessary, the indicator housing can be turned up to 90° in relation to the gauge head using the following procedure. Put the 3/32" hex wrench (1) into access hole (A) for the locking screw. Loosen the locking screw 1/2 no more than turn (180°). Turn indicator housing (2) to the desired position. Push gauge head (3) and indicator housing (2) toward each other as far as possible, and lock them into position by tightening the locking screw [while this is being done, the indicator needle should move clockwise to approximately the 8 o'clock position].

NOTE: Counter hand (4) shows which turn or revolution indicator hand (5) is on. When the dial bore gauge is correctly assembled and is at rest out of the bore, indicator hand (5) should be between the 7 o'clock and 9 o'clock positions with counter hand (4) just to the right of zero.

Replacement Of The Indicating Finger Ball

(1) When the indicating finger ball becomes flat or worn, a replacement can be installed, or the ball can be turned to a new position. Put a clean cloth under the gauge during replacement of the ball. Put indicating finger clamp (1) in position over indicating finger (2) as shown. Clamp (1) prevents movement of finger (2), which makes it easier to remove the ball and install a replacement.

(2) Push the blade of ball tool (3) under the ball through the slot in the indicating finger which intersects the ball socket. Pry up on the ball until it comes out of the socket. Ball (4) will be held between the blade and the spring clip of ball tool (3).

(3) Turn ball (4) to a new position while it is being held in the ball tool [or remove ball (4) and install a new ball in the ball tool]. Push ball (4) back into the socket with ball tool (3). Make sure the ball is fully in the socket by pushing firmly against the ball with the back of ball tool (3).

(4) Slide the ball tool out of the indicating finger. Remove indicating finger clamp (1). Check the calibration of the gauge; see SETTING THE DIAL BORE GAUGE, starting with step 7 on page 9.

Replacement Of The Gauge Point Ball

(1) When the gauge point ball becomes flat or worn, a replacement ball can be installed, or the ball can be turned to a new position using the following procedure. Remove gauge point (1) from the dial bore gauge. Put a clean cloth under the gauge point during ball replacement.

(2) Put the blade of ball tool (2) in position in the slot under the ball. Put your thumb over the ball, and slowly pry up with the ball tool until the ball comes out.

(3) Turn ball (3) to a new position while it is being held in the ball tool [or remove ball (3) and install a new ball in the ball tool]. Push ball (3) back into gauge point (1) with tool (2). Make sure the ball is fully in the gauge point. Check the calibration of the gauge; see SETTING THE DIAL BORE GAUGE, starting with step 7 on page 9.

Calibration Of The Quick Setting Wrench

(1) The quick setting wrench can be checked for calibration by using the dial bore gauge and any master ring of known size within the diameter range of 30.0 to 50.8 mm (1.181 to 2.000"). In the following procedure, a 30.2 mm (1.189") diameter master ring was used. If a master ring of another size is used, use this size instead of 30.2 mm (1.189").

(2) Install gauge point No. 1 [diameter range 30.0 to 35.2 mm (1.1811 to 1.3858")] in the dial bore gauge. Use quick setting wrench (1) to set the gauge at 30.2 mm (1.189"); see step 6 on page 7 of the topic, SETTING THE DIAL BORE GAUGE. Put dial bore gauge (2) in position in the master ring. If wrench (1) is calibrated correctly, indicator hand (3) should be within 30° of the 12 o'clock position on the dial. If the indicator hand is not within this range, go to the next step.

(3) Put gauge (2) in master ring (4), and set the gauge to read zero. The scale should be set so the zero position is at 12 o'clock. Put wrench (1) in position on gauge (2), and loosen adjusting knob set screw (5) with a 5/64" hex wrench. Turn adjusting knob (6) so the micrometer scale reads exactly 30.2. Tighten set screw (5) with knob (6) at the 30.2 reading. Check gauge (2) in master ring (4) to make sure the gauge is still set at 30.2 mm (1.189").

Repair Of The 6V6000 Dial Bore Gauge Group

The dial bore gauge group should be sent to the manufacturer for service. A letter should be with the returned gauge group, giving a description of the problem and the date of purchase from Caterpillar. Gauge groups less than one year old will be repaired under warranty, except for abuse. Cost of out-of-warranty repairs will be charged to the owner. The gauge group should be sent to the following repair center.