Calibration Masses

Table of Weight Tolerances
Which Class is Right for My Application
A balance should be calibrated using a weight with a class
tolerance factor greater than the readability of the balance.
Example: A toploading balance with readability of 0.01g
may be calibrated with a weight having a known tolerance
of at least 0.009g.
Ulti-Mass Standards. These mass standards provide the
greatest precision available from Denver Instrument. They
are ideal for use as reference standards to calibrate other
weights or for calibrating high-resolution analytical
balances. The Ulti-Mass tolerances are approximately two
times the precision of ANSI/ASTM Class 1.
ASTM Class 1. Provides high precision. Can be used as
reference standards in calibrating other weights and are
appropriate for calibration of high-precision analytical
balances.
ASTM
E617
Ulti- Class Class Class Class
Nominal Mass* 1 2 3 4
Value Tolerance Tolerance Tolerance Tolerance Tolerance
in mg in mg in mg in mg in mg
5 kg 6 12 25 50 100
2 kg 2.5 5.0 10 20 40
1 kg 1.3 2.5 5.0 10 20
500 g 0.60 1.2 2.5 5.0 10.0
300 g 0.38 0.75 1.5 3.0 6.0
200 g 0.25 0.50 1.0 2.0 4.0
100 g 0.13 0.25 0.50 1.0 2.0
50 g 0.060 0.12 0.25 0.60 1.2
30 g 0.037 0.074 0.15 0.45 0.90
20 g 0.037 0.074 0.10 0.35 0.70
10 g 0.025 0.050 0.074 0.25 0.50
5 g 0.017 0.034 0.054 0.18 0.36
2 g 0.017 0.034 0.054 0.13 0.26
1 g 0.017 0.034 0.054 0.10 0.20
500 mg 0.005 0.010 0.025 0.080 0.16
200 mg 0.005 0.010 0.025 0.060 0.12
100 mg 0.005 0.010 0.025 0.050 0.10
50 mg 0.005 0.010 0.014 0.042 0.085
20 mg 0.005 0.010 0.014 0.035 0.070
10 mg 0.005 0.010 0.014 0.030 0.060
5 mg 0.005 0.010 0.014 0.028 0.055
2 mg 0.005 0.010 0.014 0.025 0.050
1 mg 0.005 0.010 0.014 0.025 0.050
*Weights are adjusted to Class 0 tolerance but meet Class 1
specification for markings and density
ASTM Class 2. Appropriate for calibrating high-precision
toploading balances with readabilities ranging from
0.001g to 0.01g.
ASTM Classes 3 and 4. Appropriate for calibrating
balances with moderate precision, ranging from 0.01g to
0.1g.
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