ENGINE AR-PRIMARY 3032860 - Caterpillar

Starret Address: The L.S. Starrett Co.
Athol, Massachusetts 01331
Installing Probe In 1P3536 Test Fixture
1. Install the 3S3270 44.5 mm (1.75") long tip (66) in the end of the position indicator probe.2. Place 8T5108 Bushing (65) over the end of the probe mounting stem with the end of the bushing with the largest inside diameter closest to the probe body. Install the bushing so it is even with the end of the mounting stem.3. On the 1P3536 Size Setting Fixture, turn the micrometer dial (64) out (counterclockwise) until it reads 0.0.4. Using a 1/16" Allen wrench (70), turn the Allen screw on the lower end of the holder arm (71) counterclockwise until the arm is free to pivot when pressed on the lower end near the Allen screw.5. Slide holder arm (71) away from the micrometer head as far as it will go until it hits the stop at the end of it's mounting rod.6. While pressing the lower end of the holder arm (71), insert the probe tip into the V-groove (72) with the probe tip against the micrometer spindle face (73). Keep bushing (65) even with the end of the probe mounting stem and under holder arm (71).With one hand, keep the probe tip against the micrometer spindle face (73). With the other hand, pull back on the probe body to be sure the probe shaft is out as far as it will go.Tighten holder arm Allen screw (74) by turning it clockwise until the probe is securely held in the V-groove. The probe is ready to check. This setting procedure is very critical and should be checked by turning the micrometer dial one turn counterclockwise so the micrometer spindle face (73) no longer touches the probe tip.Pull out on the probe tip; and while holding it out, turn the micrometer dial slowly, one turn clockwise back to 0.0. The probe tip should not touch the spindle face (73) until the micrometer is at 0.0.Readjust the probe position if required so the probe shaft is out as far as it will go, at exactly 0.0.If the FT1982 Calibration Fixture is being used, the probe mounting boss will fit directly into the hole in the sliding mounting plate, and can be tightened with the bolt on top. The bolt on the side of the probe mounting plate allows the plate to be slid to the proper position during the checking and calibration procedures.A short tip should be used on the probe shaft when using this fixture. The probe should be positioned as described in Step 6.Checking The Accuracy
Once the probe has been installed in a test fixture, the accuracy of the system can be checked by adjusting the micrometer to move the probe shaft over it's entire range. The readings of the position indicator can be compared with the micrometer at various intervals and the difference noted. This will be the system accuracy.Although the indicator display only shows .001" resolution, the accuracy can be read to .0001"