Call Us Today: 503.692.3800 Sign In Flanges Expansion Joints Valves Fittings & Accessories Custom Machining About Us Resource Center Contact Us Home Flange Dimensional Tolerances Flange Dimensional Tolerances This table displays Flange Dimensional Tolerances by inside, outside, and contact diameter, thickness, and drilling tolerances for bolt holes diameter and spacing. These standard flange dimensional tolerances are ideal when other specifications aren't used. OUTSIDE DIAMETER When O.D. is 24" or less +0.125" , -0.0625" When O.D. over is 24" +0.125" , -0.125" INSIDE DIAMETER When I.D. is 10" or less +0.03125" , -0" When I.D. over is 10" +0.0625" , -0" CONTACT FACE DIAMETER Raised Face +0.0156" , -0.0156" DRILLING Bolt Hole Diameter +0.03125" , -0.03125" Bolt Circle Diameter +0.0625" , -0.0625" Bolt Hole Spacing +0.03125" , -0.03125" THICKNESS When nominal size is 18" or less +0.125" , -0 When nominal size is over 18" +0.1875" , -0 CONTACT US API International, Inc. 12505 SW Herman Road Tualatin, OR 97062 Phone: 503.692.3800 PRODUCTS Flanges Expansion Joints Pump Connectors Valves KLAMPz Grooved Piping System (UL/FM) Other Fittings & Accessories Custom Machining LEARN MORE About Us Contact Us Careers Catalog Flange Dimensional Tolerances Resource Center Terms and Conditions Video Library STAY CONNECTED ©2021. API INTERNATIONAL, INC.. ALL RIGHTS RESERVED. POWERED BY CIMCLOUD