Black Steel Tolerances

Specified Size (diameter or thickness)	Permissible variantion from specificed size	Permissible out-of-round or out-of-square
1	≤ 25	+ 0.25 - 0.25	0.40
2	> 25 ≤ 30	+ 0.30 - 0.30	0.45
3	> 30 ≤ 40	+ 0.40 - 0.40	0.60
4	> 40 ≤ 50	+ 0.50 - 0.50	0.75
5	> 50 ≤ 60	+ 0.60 - 0.60	0.90
6	> 60 ≤ 70	+ 0.70 - 0.70	1.05
7	> 70 ≤ 80	+ 0.80 - 0.80	1.20
8	> 80 ≤ 100	+ 0.90 - 0.90	1.35
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Specified width	Thickness tolerance (+ or -)	Thickness tolerance (+ or -)	Thickness tolerance (+ or -)	Thickness tolerance (+ or -)	Thickness tolerance (+ or -)
1		Specified thickness	Specified thickness	Specified thickness	Specified thickness	Specified thickness
2			≥6 ≤12	>12 ≤25	>25 ≤50	>50
3	≤ 25	0.2	0.2	0.25	-	-
4	> 25 ≤ 50	0.2	0.3	0.4	0.8	-
5	> 50 ≤ 100	0.2	0.4	0.5	0.8	1.2
6	> 100 ≤ 150	0.25	0.4	0.5	0.8	1.6
7	> 150 ≤ 200	0.25	0.4	0.5	0.8	-
8	> 200 ≤ 300	-	0.4	0.5	0.8	-
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Nominal leg size	Permissible variation	Permissible variation	Permissible variation
1		Leg Length	Leg Length	Out-of-square (s)
2		Over	Under
3	≤ 40	2.5	1.5	0.25
4	> 40 ≤ 75	2.5	1.5	0.4
5	> 75 ≤ 125	3	3	0.5
6	> 125 ≤ 150	3	3	0.5
7	> 150	5	3	0.5
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