SQUARE STEEL TUBE

Size by Inch  (diameter)

Thickness

Sizes by MM  (diameter)

Thickness

inch

inch

mm

mm

1/2" x 1/2"

0.065"

16mm×16mm

0.4mm～1.5mm

3/4" x 3/4"

0.049"

18mm×18mm

0.4mm～1.5mm

0.065"

20mm×20mm

0.4mm～3mm

0.083"

22mm×22mm

0.4mm～3mm

0.120"

25mm×25mm

0.6mm～3mm

1" x 1"

0.049"

30mm×30mm

0.6mm～4mm

0.058"

32mm×32mm

0.6mm～4mm

0.065"

34mm×34mm

1mm～2mm

0.072"

35mm×35mm

1mm～4mm

0.083"

38mm×38mm

1mm～4mm

0.095"

40mm×40mm

1mm～4.5mm

0.109"

44mm×44mm

1mm～4.5mm

0.120"

45mm×45mm

1mm～5mm

1 1/8" x 1 1/8"

0.035"

50mm×50mm

1mm～5mm

0.049"

52mm×52mm

1mm～5mm

0.065"

60mm×60mm

1mm～5mm

0.109"

70mm×70mm

2mm～6mm

0.120"

75mm×75mm

2mm～6mm

1 1/4" x 1 1/4"

0.049"

76mm×76mm

2mm～6mm

0.065"

80mm×80mm

2mm～8mm

0.072"

85mm×85mm

2mm～8mm

0.083"

90mm×90mm

2mm～8mm

0.109"

95mm×95mm

2mm～8mm

0.120"

100mm×100mm

2mm～8mm

0.135"

120mm×120mm

4mm～8mm

0.156"

125mm×125mm

4mm～8mm

0.188"

130mm×130mm

4mm～8mm

1 1/2" x 1 1/2"

0.049"

140mm×140mm

6mm～10mm

0.065"

150mm×150mm

6mm～10mm

0.072"

160mm×160mm

6mm～10mm

0.083"

180mm×180mm

6mm～12mm

0.109"

200mm×200mm

6mm～30mm

0.120"

220mm×220mm

6mm～30mm

0.140"

250mm×250mm

6mm～30mm

0.188"

270mm×270mm

6mm～30mm

0.250"

280mm×280mm

6mm～30mm

1 3/4" x 1 3/4"

0.065"

300mm×300mm

8mm～30mm

0.083"

320mm×320mm

8mm～30mm

0.095"

350mm×350mm

8mm～30mm

0.109"

380mm×380mm

8mm～30mm

0.120"

400mm×400mm

8mm～30mm

0.188"

420mm×420mm

10mm～30mm

2" x 2"

0.049"

450mm×450mm

10mm～30mm

0.065"

480mm×480mm

10mm～30mm

0.083"

500mm×500mm

10mm～30mm

0.109"

550mm×550mm

10mm～40mm

0.120"

600mm×600mm

10mm～40mm

0.145"

700mm×700mm

10mm～40mm

0.165"

800mm×800mm

10mm～50mm

0.188"

900mm×900mm

10mm～50mm

0.250"

1000mm×1000mm

10mm～50mm

0.312"

2 1/4" x 2 1/4"

0.188"

0.250"

2 1/2" x 2 1/2"

0.083"

0.109"

0.120"

0.188"

0.250"

0.312"

Dimensional Tolerances

Outside Diameter:

Twist:

Maximum twist per 3 feet of length

Largest outside dimension

Outside tolerance including convexity and concavity

Longest outside dimension

up to 2 1/2"

±.020"

2" to 2 1/2"inclusive

.062"

over 21/2" to 31/2" inclusive

±.025"

over 21/2" to 4" inclusive

.075"

over 31/2" to 51/2" inclusive

±.030"

over 4" to 6" inclusive

.087"

over 51/2"

±1%

over 6" to 8" inclusive

100"

Tolerances include allowance for convexity or concavity. For
rectangular sections, the tolerance calculated for the larger flat
dimension shall also apply to the smaller flat dimension. This
tolerance may be increased 50 percent when applied to the
smaller dimension, if the ratio of cross sectional dimension
is between 1.5 and 3, and 100 percent when the ratio exceeds 3.

over 8"

112"

Straightness:
Permissable variation shall be 1/8" times the number of feet of total length divided by 5:

.125" x (total length) ÷ 5

Wall Thickness:

Squareness of Sides:

Maximum allowable variation

±10%

Adjacent sides may deviate from 90° by a tolerance of plus or minus 2 degrees maximum.

(wall thickness is to be measured at the center of the flat, exclusive
of the weld area, and not at the corners)

Worner Radii:

Flash:

The radius of any outside corner shal not exceed three times
the specified wall thickness

Structural tubing usually is supplied flash-in. The height of the
flash will vary with the wall thickness of the tube.