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Tolerances on Openings

The tolerance on the opening is the allowable deviation for the stated hole size in a perforated sheet or plate. The tolerance of the opening is a measurement of the minimum opening size only, and does not refer to the dimensions of the hole as it progresses through the thickness of the sheet.

Many factors can influence the size of the hole including the type and thickness of material, the punch and die clearance, and the use of plasma or oxy-fuel cutting. During punching, the top surface of the material will “rollover” resulting in a finished hole that is slightly smaller than the punch that created it. The amount of “rollover” usually increases with material thickness, but varies greatly with material type and die clearance.

The chart below is the standard tolerance for hole size that is applied to all orders unless noted otherwise. Please contact us to discuss any special requirements you may have.

Opening Tolerances

Perforated Opening Tolerance on Openings
Standard (metric) MM USA Industrial Standard Inch Additional Sizes Inch Standard (metric) MM USA Industrial Standard Inch
125.0 5 - ± 2.5 ± 1.100
- - 4-1/2 - ± 0.090
106.0 4-1/4 - ± 2.1 ± 0.085
100.0 4 - ± 2.0 ± 0.080
- - 3-3/4 - ± 0.075
90.0 3-1/2 - ± 1.8 ± 0.070
- - 3-1/4 - ± 0.065
75.0 3 - ± 1.5 ± 0.060
- - 2-3/4 - ± 0.055
63.0 2-1/2 - ± 1.3 ± 0.050
- - 2-1/4 - ± 0.045
53.0 2-1/8 - ± 1.1 ± 0.043
50.0 2 - ± 1.0 ± 0.040
- - 1-7/8 - ± 0.038
45.0 1-3/4 - ± 0.9 ± 0.035
- - 1-5/8 - ± 0.033
37.5 1-1/2 - ± 0.8 ± 0.030
- - 1-3/8 - ± 0.028
31.5 1-1/4 - ± 0.6 ± 0.025
- - 1-3/16 - ± 0.024
- - 1-1/8 - ± 0.023
26.5 1-1/16 - ± 0.5 ± 0.021
25.0 1 - ± 0.5 ± 0.020
- - 15/16 - ± 0.019
22.4 7/8 - ± 0.46 ± 0.018
- - 13/16 - ± 0.016
19.0 3/4 - ± 0.38 ± 0.015
- - 11/16 - ± 0.014
16.0 5/8 - ± 0.32 ± 0.013
- - 9/16 - ± 0.012
13.2 17/32 - ±0.30 ± 0.012
12.5 1/2 - ± 0.28 ± 0.011
- - 15/32 - ± 0.011
11.2 7/16 - ± 0.28 ± 0.011
9.5 3/8 - ± 0.28 ± 0.010
8.0 5/16 - ± 0.26 ± 0.010
6.7 17/64 - ± 0.25 ± 0.009
6.3 1/4 - ± 0.25 ± 0.009
5.6 7/32 - ± 0.24 ± 0.009
4.75 3/16 - ± 0.21 ± 0.008
4.00 5/32 - ± 0.19 ± 0.007
3.35 0.127 - ± 0.17 ± 0.006
* (1/8) * * *
2.80 7/64 - ± 0.150 ± 0.006
2.36 3/32 - ± 0.135 ± 0.005
2.00 0.078 - ± 0.125 ± 0.005
1.70 0.066 - ± 0.110 ± 0.004
1.40 0.055 - ± 0.100 ± 0.004
1.18 0.045 - ± 0.085 ± 0.003
1.00 0.039 - ± 0.700 ± 0.003
0.830 0.032 - ± 60pm ± 0.002
0.710 0.027 - ± 50pm ± 0.002
0.600 0.023 - ± 45pm ± 0.002
0.500 0.020 - ± 40pm ± 0.002

*Round holes only.