OK, here is the calibration info I've got for the As you work thru the calibration procedure, if you see anything that needs adding, removing, or re-wording please let me know. I've posted this to the forum, but couldn't find the thread this morning.
Adjusting the HR-150A hardness tester following the instructions on the directions below works like a champ. In figure 7 below you can the 3 main calibration screws, #5 is the center with a lock nut, the two outside silver screws do not have lock nuts. The center screw with lock nut adjusts the pointer needle.
1: If the Pin End of Small Level is not locate in the middle of hole of as shown in Figture 8, loosening the Screw# 1&2 in Figture 7 and moving the bar right or left to make the Pin End of Level in the middle of hole as Figture 9, then screwing it down. This position might require adjusting the pivot pins holding the center bar. This step should only be required in a badly out of calibration tester.
2: With the main dial in front turned so the C (call this the zero position) is exactly at the top 12 Oclock position. Note position of needle on main dial, is it somewhere between 11 and 1 O'clock? If so, proceed to step #2. If not, use a 7mm wrench to hold lock nut on center screw (#5), hold screw with screwdriver and loosen nut with wrench. Playing with this screw the needle can be adjusted easy between 11 and 1 O'clock. That's close enough for now.
3: Take the ~62 Rc test block and take a reading, note if reading low or high. Here I then take a 1/4" or 3/8" HSS tool bit (from lathe) and test it. Note how it reads compared to test block. Use this HSS tool steel for most of testing to save many dimples in test block. The HSS steel should read somewhere from 62 to 67 Rc depending on metal.
4: If reading is low, loosen the two outside silver screws and move plate forwards toward dial a small tad. If reading is high, then move plate backward a tad. Small movement will make a fairly large difference in calibration. After tightening the two outside screws, the big needle will again need adjusting with the center screw to somewhere between 11 and 1 O'clock.
5: Test HSS steel again. This does take a good bit of playing around to get correct. With calibration set at 62 Rc, I found my low end still didn't read correctly, but that's not a real problem since I only use that for testing backsprings and that reading isn't as critical as the blade - in my opinion anyway.
6: Once the calibration is complete, the needle on main dial should be adjusted to the 12 Oclock position, and with the test result reading Rc value of test block.
This procedure works for me. I'd be interested in hearing if it works for other folks.
Ken H>
Adjusting the HR-150A hardness tester following the instructions on the directions below works like a champ. In figure 7 below you can the 3 main calibration screws, #5 is the center with a lock nut, the two outside silver screws do not have lock nuts. The center screw with lock nut adjusts the pointer needle.
1: If the Pin End of Small Level is not locate in the middle of hole of as shown in Figture 8, loosening the Screw# 1&2 in Figture 7 and moving the bar right or left to make the Pin End of Level in the middle of hole as Figture 9, then screwing it down. This position might require adjusting the pivot pins holding the center bar. This step should only be required in a badly out of calibration tester.
2: With the main dial in front turned so the C (call this the zero position) is exactly at the top 12 Oclock position. Note position of needle on main dial, is it somewhere between 11 and 1 O'clock? If so, proceed to step #2. If not, use a 7mm wrench to hold lock nut on center screw (#5), hold screw with screwdriver and loosen nut with wrench. Playing with this screw the needle can be adjusted easy between 11 and 1 O'clock. That's close enough for now.
3: Take the ~62 Rc test block and take a reading, note if reading low or high. Here I then take a 1/4" or 3/8" HSS tool bit (from lathe) and test it. Note how it reads compared to test block. Use this HSS tool steel for most of testing to save many dimples in test block. The HSS steel should read somewhere from 62 to 67 Rc depending on metal.
4: If reading is low, loosen the two outside silver screws and move plate forwards toward dial a small tad. If reading is high, then move plate backward a tad. Small movement will make a fairly large difference in calibration. After tightening the two outside screws, the big needle will again need adjusting with the center screw to somewhere between 11 and 1 O'clock.
5: Test HSS steel again. This does take a good bit of playing around to get correct. With calibration set at 62 Rc, I found my low end still didn't read correctly, but that's not a real problem since I only use that for testing backsprings and that reading isn't as critical as the blade - in my opinion anyway.
6: Once the calibration is complete, the needle on main dial should be adjusted to the 12 Oclock position, and with the test result reading Rc value of test block.
This procedure works for me. I'd be interested in hearing if it works for other folks.
Ken H>
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