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| Outside Diameter | When O.D. is 24" or less | ±1.6mm﹡ | 
| Inside Diameter | 10" and smaller | ±0.8mm | 
| 12" thru 18" | ±1.6mm | |
| 20" and larger | +3.2mm, -1.6mm | |
| Outside Diameter of hub | 5" and smaller | +2.4mm, -0.8mm﹡ | 
| 6" and larger | +4.0mm, -0.8mm | |
| Diameter of contact face | 1/16" rasied face tongue and groove male, female | ±0.8mm | 
| 1/4" rasied face tongue and groove male, female | ±0.4mm | |
| Diameter of hub at base | when hub base is 24" or smaller | ±1.6mm﹡ | 
| Diameter of hub at point of welding | 5" and smaller | +2.4mm, -0.8mm | 
| 6" and larger | +4.0mm, -0.8mm | |
| Drilling | Bolt circle | ±1.6mm | 
| Bolt hole spacing | ±0.8mm | |
| Eccentricity of bolt circle with respect to facing | 2 1/2" and smaller: 0.8mm, max﹡ | |
| Eccentricity of bolt circle with respect to bore | 3" and larger: 1.6mm, max﹡ | |
| Thickness | 18" and smaller | +3.2mm, -0mm | 
| 20" and larger | +4.8mm, -0mm | |
| Length of thru hub | 10" and smaller | ±1.6mm | 
| 12" and larger | ±3.2mm | 
| Outside Diameter | When O.D. is 24" or less | ±1.6mm﹡ | 
| Inside Diameter | Threaded | Within limits on boring gauge | 
| Socket welding, Slip-on and Lap joint, 10" and smaller | +0.8mm, -0mm | |
| Socket welding, Slip-on and Lap joint, 12" and larger | +1.6mm, -0mm | |
| Outside Diameter of hub | 5" and smaller | +2.4mm, -0.8mm﹡ | 
| 6" and larger | +4.0mm, -0.8mm | |
| Diameter of contact face | 1/16" rasied face tongue and groove male, female | ±0.8mm | 
| 1/4" rasied face tongue and groove male, female | ±0.4mm | |
| Diameter of counterbore | same as for inside diameter | |
| Drilling | Bolt circle | ±1.6mm | 
| Bolt hole spacing | ±0.8mm | |
| Eccentricity of bolt circle with respect to facing | 2 1/2" and smaller: 0.8mm, max﹡ | |
| Eccentricity of bolt circle with respect to bore | 3" and larger: 1.6mm, max﹡ | |
| Thickness | 18" and smaller | +3.2mm, -0mm | 
| 20" and larger | +4.8mm, -0mm | |
| Length of thru hub | 10" and smaller | ±1.6mm | 
| 12" and larger | ±3.2mm | |
| A flange is a method of connecting pipes, valves, pumps and other equipment to form a piping system. | View more flanges as below: | 
