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17 Piece - Class M2 - Calibration Weight Set

PN: CALWTSET-RED-707MFR PN: SCMWEIGHTSET 4 stars (4) product reviews product questions
in stock
MSRP: $28.99 Old Will's Price: $16.50 Quantity

My Weigh Calibration Weight Set

Class M2 ~ 17 piece weight set

"In A Nutshell"
(1) 100 g+/- 15 mg
(1) 50 g+/- 10 mg
(1) 20 g+/- 8 mg
(1) 10 g+/- 6 mg
(1) 5 g+/- 5 mg
(1) 2 g+/- 4 mg
(1) 1 g+/- 3 mg
(1) 500 mg+/- 2.5 mg
(2) 200 mg+/- 2 mg
(1) 100 mg+/- 1.5 mg
(1) 50 mg-
(1) 20 mg-
(1) 10 mg-

Product Details

Use these calibration weights alone, or combine them to accurately calibrate your digital weighing scale.

Additional Images

Customer Reviews

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Good price and great kit 5 stars

Good price for this kit, works as expected.

Reviewed by: Tony from Cleveland on (10/12/2014)
works for me 4 stars

I just wanted a few small weights to set spring tension on the keys of a small pipe organ. 5 gram increments would have been OK. Got much more than I needed, but the price was right. My only complaint was that the 5g weight wasn't flat on the bottom, so I ground of a few mgs!

Reviewed by: David from Utah on (4/8/2013)
Great product and an even better retailer. 5 stars

I bought this set of weights to check the accuracy of my reloading scale. Unfortunately, the set came without the plastic cover for the wafer weights. Fortunately, after one call to Will Knott, a shiny new cover arrived at my door step in about 2 days, no charge. Unbelievably great customer service! The weights are good too.

Reviewed by: B. Bellas from New Boston, MI on (3/27/2013)
17M2 piece calibration weight set 4 stars

A good value for my needs. All weights within specifications except for the 2 mg (2 included) and 1 mg weights. The 2 mg weights came in at 2.015 and 2.025 grams. The 1 mg weight a dismal .830 grams. These were tested with an electronic powder reloading scale and a precise diamond-weighing (carat weights) balance scale.

Reviewed by: Bill Burchell from South Bend, IN on (2/25/2012)

Questions and Answers

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Q: Does the weight set come with certificate of calibration? Asked by: Robert (9/18/2014) answer this question

A: Hey there Robert,
No this weight set does not come with a certificate of calibration.

Answered by: Brandon (9/18/2014)
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Q: Just want to check about tolerances: If I am combining weights for example to get 150 g and have the 100g +/- 15mg and the 50g +/- 10 mg my total error would be +/- |15+10| or +/- 25mg, right? or if I add up to 180g with the 100g, 50g, 20g, & 10g, the total error possible would be +/- |15 + 10 + 8 + 6| or +/- 39mg. Thanks. Asked by: mb (1/26/2015) answer this question

A: Hey there mb,

Yes that is correct. You have to take into account the tolerances of the weights themselves, and the tolerances of the scale being used. That doesn't mean the added weight value WILL be off by that much, but it helps to know just how far off the weight value COULD be.

Take care,

Answered by: Brandon (1/30/2015)
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Q: Can this calibration weight set be usable for the GEM Pro 250? Asked by: Bob Sylvain (8/3/2015) answer this question

A: Hey there Bob,

The weights within the weight set are all M2 class. That class of weight will get the job done, however I would recommend using a higher class, more precise weight to calibrate the GemPro 250 since it's so sensitive and precise.

Rule of Thumb: The tolerance for the calibration weight you chose should have one more decimal place than the resolution for your scale. In this example, I would recommend the ASTM Class 3 Calibration weight which has a tolerance of plus or minus 0.0006 grams. The resolution of the GemPro 250 is 0.001 grams.

Take care,

Answered by: Brandon (8/5/2015)
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Q: Odd question but I would like to use these for dual purpose. One as intended, one as not. Can you tell me what the OD of the larger weights are? I am hoping for less than 2.5". I suppose I would like to also know which weight has the maximum weight with a 2.5" clearance. Asked by: Frazier (6/16/2015) answer this question

A: Hey there Frazier,

The largest weights are, of course, the 50 gram and the 100 gram versions. The 50 gram weight is approximately 1.15 inches tall and 0.65 inches wide. The 100 gram weight is 1.5 inches tall and 0.8 inches wide.

Take care,

Answered by: Brandon (6/17/2015)
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Q: What are the diameters of each weight? Thanks! Asked by: Alan (4/7/2016) answer this question

A: Hey there Alan,


The milligram weights are square/rectangular pieces of metal that vary in size.

Take care,

Answered by: Brandon (4/8/2016)
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