Help with HR-150A

A

Al A

Joined
Apr 3, 2022
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Hello, long time lurker first time poster. Please forgive me if I'm in the wrong forum.

I just picked up an HR-150A hardness tester, and I'm having some weird problems. I suspect they may be related to the temperature in my (unheated) shop, but I'm not convinced and figured I'd ask if anyone else has seen something similar.

I had to clean up a bunch of seized up grease when I first opened up the machine, and have lubricated everything appropriately and everything appears to move smoothly at this point. I followed the directions for checking hardness:
1. Place material on work surface (puck of known hardness)
2. Raise work surface up to indenter, apply pressure until small dial is pointing at the red dot (big needle rotates three times) to apply minor load
3. Pull load lever to apply major load, wait for lever to stop moving
4. Pull unload lever to remove major load

After applying the minor load, the big needle never moved again. In addition, when I bring the work table down to release the puck, the dial does not automatically reset. In addition, the hydraulic buffer is not in contact with the major load whatsoever once the minor load is applied in step 2, leading me to believe that the major load is already applied once at that point on my machine. I attempted to raise the hydraulic arm as much as possible, but that did not change the results at all.

I then tried the following:
1. Place material on work surface (puck of known hardness)
2. Raise work surface until internal lever arm is in contact with the weight hangar (zero minor load)
3. Pull load lever to apply major load, wait for lever to stop moving
4. Pull unload lever to remove major load

At this point, the big needle does move, and indicates a reliable hardness value that is fairly close to the known puck (read RC52, 52, 53 over three tests, puck is RC58). I have a few more pucks with different hardness on order, so I can check those as well to see if this method of use is reliable, but it's so far from the intended method that I don't have a lot of confidence in the data I'm getting.

Thanks,
Al
 
Al A said:
Hello, long time lurker first time poster. Please forgive me if I'm in the wrong forum.

I just picked up an HR-150A hardness tester, and I'm having some weird problems. I suspect they may be related to the temperature in my (unheated) shop, but I'm not convinced and figured I'd ask if anyone else has seen something similar.

I had to clean up a bunch of seized up grease when I first opened up the machine, and have lubricated everything appropriately and everything appears to move smoothly at this point. I followed the directions for checking hardness:
1. Place material on work surface (puck of known hardness)
2. Raise work surface up to indenter, apply pressure until small dial is pointing at the red dot (big needle rotates three times) to apply minor load
3. Pull load lever to apply major load, wait for lever to stop moving
4. Pull unload lever to remove major load

After applying the minor load, the big needle never moved again. In addition, when I bring the work table down to release the puck, the dial does not automatically reset. In addition, the hydraulic buffer is not in contact with the major load whatsoever once the minor load is applied in step 2, leading me to believe that the major load is already applied once at that point on my machine. I attempted to raise the hydraulic arm as much as possible, but that did not change the results at all.

I then tried the following:
1. Place material on work surface (puck of known hardness)
2. Raise work surface until internal lever arm is in contact with the weight hangar (zero minor load)
3. Pull load lever to apply major load, wait for lever to stop moving
4. Pull unload lever to remove major load

At this point, the big needle does move, and indicates a reliable hardness value that is fairly close to the known puck (read RC52, 52, 53 over three tests, puck is RC58). I have a few more pucks with different hardness on order, so I can check those as well to see if this method of use is reliable, but it's so far from the intended method that I don't have a lot of confidence in the data I'm getting.

Thanks,
Al
Click to expand...

Cycle the air out of the dash pot by doing a dry cycling (load and unload without anything on the anvil making contact with the indenter)
Oil carpet should be saturated with oil when enough cycles are done.

Make sure your dial is zeroed, adjust your pin screw as needed and make sure the lever arm is attached to the dial lever properly.

Keep your major load application speed within 3-4sec by adjusting the oil needle dial next to the dash pot.
 
Thank you for your reply!

Unfortunately, no success. I dry cycled a dozen times, excellent saturation in the oil carpet.

I re-zeroed the pin screw, but I can't figure out how the dial lever should be attached to the big lever arm. There isn't an obvious missing component either, or any breakage that I can detect. Given the amount of force required to move the dial, I can't believe it's supposed to be gravity return. Do you have a picture of the proper setup?

Major load application speed is fairly slow, ~8-10 seconds, but I think that's the oil being cold. I plan to move the unit into the house this evening once I've purchased a cart my wife won't divorce me over bringing inside, so that should solve the oil viscosity issue.
 
Al A said:
Thank you for your reply!

Unfortunately, no success. I dry cycled a dozen times, excellent saturation in the oil carpet.

I re-zeroed the pin screw, but I can't figure out how the dial lever should be attached to the big lever arm. There isn't an obvious missing component either, or any breakage that I can detect. Given the amount of force required to move the dial, I can't believe it's supposed to be gravity return. Do you have a picture of the proper setup?

Major load application speed is fairly slow, ~8-10 seconds, but I think that's the oil being cold. I plan to move the unit into the house this evening once I've purchased a cart my wife won't divorce me over bringing inside, so that should solve the oil viscosity issue.
Click to expand...
If you turn the dial to its back it should have a slot with what looks like a tiny handle with a slot attached to a plunger, your lever arm should fit in that slot that way as the lever arm raises and lowers the dial hand moves in correspondence to the lever arm moving.

8 to 10 seconds application speed of total test forces is too slow and may throw off your readings due to creep.
You'll have to adjust your oil needle with the dial by the dashpot accordingly.

These machines are designed to operate best at room temperature in a clean environment with low vibration. Also confirm your hardness tester is level and shim it up or use an adjustable table if needed.
 
Resolution!

I had two problems going on.

First, the clockwork mechanism had insufficient lubrication. While the internal components moved freely and well, the annular weight was not. Once lubricated with 3-in-1 oil, it re-sets to zero just fine.

The second problem was the weight height. I'm not entirely comfortable with my solution as it feels like I'm taking the machine outside of intended parameters, but it is working now, and results are hard to argue with. I had to set the loading bar higher than the jam nut thread height to get the weights high enough to pre-load properly. One jam nut is now floating on top of the hydraulic assembly, and the other is about halfway on the very bottom thread.

It does not read low hardness values well, but it is now pretty reliable around RC 55-60 which is what I care about.
 
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