Operating Instructions & Parts Manual
Page 6
Seating Your Diamond:
Caution: To ensure accuracy, mount the indenter by sliding it in the holder as far as possible and then securing the
indenter by tightening the set screw finger-tight only.
Place HRC test block on the small round anvil and begin by turning the handwheel clockwise until the block just
touches the diamond. At this point, continue rotating the handwheel until the large needle goes around approx. 3
revolutions. Let the machine sit idle for a few seconds and then loosen the set screw. Wait a few more seconds and
then tighten the set screw back up. This will allow the diamond to be “seated” in the shank. Take the load off by
turning the handwheel counter-clockwise and you can begin following instructions below.
Rotate the weight adjustment knob until the required weight scale is aligned with the alignment mark on the frame of
the machine.
1. Prepare the test specimen properly. Be sure that the top and bottom surfaces of the specimen are clean and free
of any grease, oil dirt, etc and free of any burrs or debris.
2. For small specimens (under 3" maximum length or diameter) use the small round anvil. Use the large anvil for
larger specimens. Use the V-shaped anvil for round or curved specimens.
Warning!
Do not test any specimen that cannot be safely and properly
positioned on and supported by the tester anvil.
Operation:
Determine the proper indenter, scale and weight for the material hardness to be tested (see last page in manual).
Mount the required indenter in the indenter holder using the set screw on the side of the holder.
Test Procedure
Test procedure consists of a preload of the specimen using the force of the elevation screw and a test load using the
weights and lever arm assembly. Be sure that the weight reset handle is in rest(“unload”) position.
1. Mount specimen on required anvil. Rotate the elevation screw threaded collar clockwise slowly until the
specimen contacts the indenter. Be sure to position specimen so the indenter contacts clean, untested material.
2. Preload the specimen by rotating the leadscrew collar slowly until the large needle on the dial indicator rotates
three (3) revolutions. Stop rotation of handwheel when the large needle is within 3 hash marks of vertical(TDC)
Caution: As the large needle is properly rotated 3 revolutions, the small needle rotates counterclockwise 90°
to vertical at the red dot. If the large needle overshoots vertical by more than 5 hash marks, the test is invalid
and must be repeated from step 1.
3. Rotate the bezel so that the hash mark at the “0” mark at the top of the dial is aligned with the large needle.
4. Pull the weight release handle to apply the major load. Wait until the large needle stops rotating, approx. 5-8
seconds. This 5-8 second “dwell” time can be adjusted by turning valve on dashpot.
5. Slowly push the weight reset handle back until it resets and locks in the reset position.
6. Read the material hardness from the required scale on the dial.
7. Rotate the handwheel counterclockwise to lower and release the specimen.
Figure 4 - Dial Indicator
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