This instrument has a factory-set preload and comes calibrated and ready to use. Due to the preload, the dial gauge does not read zero or align vertically at rest. Do not turn the dial indicator unless the unit needs to be reset.
Insert the shank of the Model 415B Metal Hardness Tester securely into a 1/2 inch chuck on a drill press, mill, or lathe. A sturdy setup is essential for proper operation and accurate measurements. Allow sufficient clearance between the hardness tester and the drill press platform for the test block or sample being tested. The surface of the piece to be tested must be smooth, clean, and perpendicular to the long axis of the instrument.
The tester is shipped ready to use, however, a calibration check may be performed as needed. Insert a clean, smooth portion of the test block (supplied with the hardness tester) directly beneath the indenter in the base of the hardness tester. For accurate readings and to prevent damaging the indenter, all measurements should be made at least three diameters apart. Carefully lower the quill or handle until the indenter contacts the test block surface. Then slowly increase the force until the base of the hardness tester makes full contact with the test block surface. While exerting sufficient force to hold the base of the hardness tester in full contact with the test block, and the dial pointer steady, check that the tester reads the test block hardness.
When making tests, it is important that the test block or sample be properly supported on a heavy, flat surface. Per ASTM E-18, only the block's test surface with the PTC® mark should be used; this surface must not be reworked.
Raise the hardness tester and move the test block to an unused portion of the block. If any discrepancies in readings occur, adjust the rim of the gauge to average out the readings. Run the test at least three times and adjust the rim of the gauge to set the dial at the average of the readings. This is very important, since minor hardness fluctuations may occur in even something as precise as a test block. Once this has been adjusted, the hardness tester is good for many consecutive readings checking it against the test block again.
The Model 415B is now calibrated at a known hardness value and again ready for use. Remove the test block and substitute the metal part to be tested. Carefully lower the drill press handle or quill until the indenter rests on the sample's surface, then slowly increase the force until the base of the hardness tester fully contacts the metal's surface. Read the equivalent Rockwell B Scale hardness directly on the dial. Make several readings and average the results.