LiveLife
Member
For those curious about how accurate "cheaper" calipers and digital scales perform, I did some testing with Lyman shooters check weights and a new feeler gauge.
Products tested:
- New Frankford Arsenal 6" dial calipers
- ~ 20 year old Frankford Arsenal (MidwayUSA) 6" dial calipers
- ~ 3 year old Harbor Freight 6" digital calipers
- New Frankford Arsenal DS-750 digital scale
- ~ 20 year old Frankford Arsenal (MidwayUSA) digital scale
Check weight range: 0.5, 1, 2, 5, 10, 20 grains
Feeler gauge range: .0015", .0020", .0025", .003", .004", .005"
Here are the results (To factor in effects of fluorescent lighting, two CFL clamp lights were used over the bench during the duration of testing with ambient temperature of 68F):
- Harbor Freight 6" digital calipers bought about 3 years ago measured .0015", .002", .0025", .003", .004", .005".
- New Frankford Arsenal 6" dial calipers measured .002", .003", .004", .005" (needle tip was between lines for .0015" and .0025").
- Frankford Arsenal (MidwayUSA) 6" dial calipers about 20 years old measured .002", .003", .004", .005" (needle tip was between lines for .0015" and .0025").
- The check weights were weighed on two Ohaus 10-10 scales and they weighed 0.5, 1, 2, 5, 10, 20 grains on both 10-10 scales. The 10 grain check weight was weighed using both the large poise or the micrometer poise set to 10 grains and both methods gave the same weight.
- New Frankford Arsenal DS-750 digital scale with 2 AAA batteries read 0.5, 1, 2, 4.9 briefly then read 5, 10, 20 grains. After the scale was calibrated (first calibration out of the box), it read exactly 0.5, 1, 2, 5, 10, 20 grains.
- Frankford Arsenal (MidwayUSA) digital scale about 20 years old with 2 new CR2032 batteries read 0.4, 1, 2, 4.9, 10, 20 grains. After the scale was calibrated (it was last calibrated several months ago), it read 0.4, 1, 2, Flickered between 4.9/5.0, 10, 20 grains.
Summary - Although Harbor Freight digital calipers were accurate, I would suggest you check their dial calipers with feeler gauges as I found over the years, many to be off by .001"+ and felt gritty without smooth action so I never bought any. The digital calipers I checked were accurate and I would endorse them. If you are looking for dial calipers, I would not hesitate to recommend Frankford Arsenal dial calipers.
I have always used the old Frankford Arsenal digital scale knowing that it had 0.1 gr variance but it was fast for weighing bullets and military .308 cases for sorting. The new DS-750 model is certainly accurate enough for me and both digital scales never showed any effects of florescent (CFL) lighting I used directly over the bench.
Suggestion for digital scale use - The old FA digital scale came with specified operating temperature range of 59F - 95F and the new FA digital scale came with specificed operating temperature range of 50F - 86F. I found that using the old FA digital scale outside of the temperature range and/or with weak batteries resulted in inconsistent scale readings.
Products tested:
- New Frankford Arsenal 6" dial calipers
- ~ 20 year old Frankford Arsenal (MidwayUSA) 6" dial calipers
- ~ 3 year old Harbor Freight 6" digital calipers
- New Frankford Arsenal DS-750 digital scale
- ~ 20 year old Frankford Arsenal (MidwayUSA) digital scale
Check weight range: 0.5, 1, 2, 5, 10, 20 grains
Feeler gauge range: .0015", .0020", .0025", .003", .004", .005"
Here are the results (To factor in effects of fluorescent lighting, two CFL clamp lights were used over the bench during the duration of testing with ambient temperature of 68F):
- Harbor Freight 6" digital calipers bought about 3 years ago measured .0015", .002", .0025", .003", .004", .005".
- New Frankford Arsenal 6" dial calipers measured .002", .003", .004", .005" (needle tip was between lines for .0015" and .0025").
- Frankford Arsenal (MidwayUSA) 6" dial calipers about 20 years old measured .002", .003", .004", .005" (needle tip was between lines for .0015" and .0025").
- The check weights were weighed on two Ohaus 10-10 scales and they weighed 0.5, 1, 2, 5, 10, 20 grains on both 10-10 scales. The 10 grain check weight was weighed using both the large poise or the micrometer poise set to 10 grains and both methods gave the same weight.
- New Frankford Arsenal DS-750 digital scale with 2 AAA batteries read 0.5, 1, 2, 4.9 briefly then read 5, 10, 20 grains. After the scale was calibrated (first calibration out of the box), it read exactly 0.5, 1, 2, 5, 10, 20 grains.
- Frankford Arsenal (MidwayUSA) digital scale about 20 years old with 2 new CR2032 batteries read 0.4, 1, 2, 4.9, 10, 20 grains. After the scale was calibrated (it was last calibrated several months ago), it read 0.4, 1, 2, Flickered between 4.9/5.0, 10, 20 grains.
Summary - Although Harbor Freight digital calipers were accurate, I would suggest you check their dial calipers with feeler gauges as I found over the years, many to be off by .001"+ and felt gritty without smooth action so I never bought any. The digital calipers I checked were accurate and I would endorse them. If you are looking for dial calipers, I would not hesitate to recommend Frankford Arsenal dial calipers.
I have always used the old Frankford Arsenal digital scale knowing that it had 0.1 gr variance but it was fast for weighing bullets and military .308 cases for sorting. The new DS-750 model is certainly accurate enough for me and both digital scales never showed any effects of florescent (CFL) lighting I used directly over the bench.
Suggestion for digital scale use - The old FA digital scale came with specified operating temperature range of 59F - 95F and the new FA digital scale came with specificed operating temperature range of 50F - 86F. I found that using the old FA digital scale outside of the temperature range and/or with weak batteries resulted in inconsistent scale readings.
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