Standard Thickness Gage Calibration

Purpose

The purpose of this procedure is to provide general instructions for the calibration of standard thickness gages.

Scope

This general procedure shall be used in the absence of any specific calibration procedure for standard thickness gages.

Procedure

A standard thickness gage is actually made up of a series of thin plastic strips used to standardize thickness-measuring instruments.

Preliminary Instructions and Notes

1. Read this entire procedure before beginning the calibration.
2. Calibration shall be performed in an environment that conforms to Manufacturer Specifications.
3. The standard thickness gage will hereafter be referred to as the Instrument Under Test (IUT).
4. Verify that the IUT is clean.
5. Visually examine the IUT for any condition that could cause errors in the calibration.
6. If any of the requirements cannot be met, refer to the applicable manufacturer manual.
7. If a malfunction occurs or a defect is observed while calibration is in progress, the calibration shall be discontinued and necessary corrective action taken; if corrective action affects a measurement function previously calibrated, the function shall be recalibrated before the remainder of the procedure implemented.

Reference Material

Applicable Manufacturers Manual or Brochures.

Specifications

The specifications of the IUT are determined by the applicable manufacturer's documentation. If the manufacturer's documentation is not available, then the specifications identified in this procedure are used.

The following are "nominal diameters" and tolerances for all standard thickness gages:

• Accuracy of each strip is +/- 0.000050 inch.

Equipment Required

The Standards listed below should be selected on the basis of their higher accuracy level when compared to the IUT. Equivalent Standards must be equal to or better than the Minimum-Use-Specification.

Minimum-Use-Specifications for Standards listed are 1/4 the accuracy required by the IUT.

Detailed Procedure

1. Set the tail stock pressure of the Standard Measuring Machine to one pound.
2. Zero the micrometer dial along with the electro limit gage.
3. Place the IUT between the anvils of the Standard Measuring Machine.
4. Hold the IUT so its center is aligned with the anvils of the Standard Measuring Machine.
5. Make three measurements within a 1/2-inch area and average the three readings. Compare the reading with the specifications listed in section 3.3 of this procedure.
6. Repeat steps 3 through 3 for each plastic strip in the IUT.

Reason for Reissue

Revision A - First Release