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.
Without removing the blue cap, insert the shank of the Model 415C securely into a 1/2 inch chuck in your mill, drill press, or lathe. A sturdy setup is essential for proper operation and long diamond life. The surface of the piece to be tested must be smooth, clean, and perpendicular to the long axis of the instrument. Allow sufficient clearance between the hardness tester and the drill press platform for the test block or sample being tested. Do not let the diamond indenter drag on the test block or test piece as the diamond will break.
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 diamond tipped indenter in the base of the hardness tester. All measurements must be made at least 3 diameters apart to avoid breaking the diamond indenter. Remove the blue cap and 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 gauge pointer steady, check to see that the tester reads the test block hardness. The block must be held in position firmly, any movement while a load is on the indenter will break the diamond tip.
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. 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, as 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 before checking it against the test block again.
The Model 415C Hardness Tester 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. Remember, it is critical that the sample is held firmly and not allowed to shift or move during the test as the resulting motion will break the diamond. Carefully lower the drill press feed handle or quill until the diamond tipped 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 C Scale hardness directly on the dial. Make several readings and average the results.