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GSTIN 27ADJPJ5621J1ZF · Reference copy · 11 November 2026
STEEL IMPEX INDIA · ENGINEERING REFERENCE
Flange Stud Bolt Size & Length Chart | ASME Classes
Flange stud diameters, quantities and lengths by NPS and class. Keep raised-face and ring-joint requirements, inch threads and reference notes distinct. Select the exact size/class and facing used by the order; keep the stated source units and revision with the values.
Open reference Common questionsASME B16.5 flange bolting — manufacturer reference lengths · Class 150 · mm · All listed sizes
Published dimensional reference snapshot, retrieved 2026-11-11. Confirm the specified standard edition, tolerances and manufacturer drawing before manufacture or purchase. A missing value remains Not listed.
Metric dimensions are converted from the source inch values; source rounding limits precision.
Lengths are nominal stud references for a flange-to-flange joint with two heavy hex nuts. RF heights are 1/16 in for Classes 150/300 and 1/4 in for Class 400 upward. Check the required effective-thread/end-point convention, gasket, washers, thread projection and assembly drawing before ordering. Add the actual thickness of any spacer or wafer component; lap-joint assemblies need their stub-end allowance.
Nominal inch stud sizes are converted for the metric display; this does not turn an inch stud into an interchangeable metric fastener. Use the custom stud calculator for a nonstandard assembly.
Lengths are nominal stud references for a flange-to-flange joint with two heavy hex nuts. RF heights are 1/16 in for Classes 150/300 and 1/4 in for Class 400 upward. Check the required effective-thread/end-point convention, gasket, washers, thread projection and assembly drawing before ordering. Add the actual thickness of any spacer or wafer component; lap-joint assemblies need their stub-end allowance.
Nominal inch stud sizes are converted for the metric display; this does not turn an inch stud into an interchangeable metric fastener. Use the custom stud calculator for a nonstandard assembly.
| NPS (in) | Studs per joint | Heavy hex nuts per joint | Nominal stud diameter | RF stud length |
|---|---|---|---|---|
| 0.5 | 4 studs | 8 nuts | 12.7 mm | 57.15 mm |
| 0.75 | 4 studs | 8 nuts | 12.7 mm | 63.5 mm |
| 1 | 4 studs | 8 nuts | 12.7 mm | 63.5 mm |
| 1.25 | 4 studs | 8 nuts | 12.7 mm | 69.85 mm |
| 1.5 | 4 studs | 8 nuts | 12.7 mm | 69.85 mm |
| 2 | 4 studs | 8 nuts | 15.875 mm | 82.55 mm |
| 2.5 | 4 studs | 8 nuts | 15.875 mm | 88.9 mm |
| 3 | 4 studs | 8 nuts | 15.875 mm | 88.9 mm |
| 3.5 | 8 studs | 16 nuts | 15.875 mm | 88.9 mm |
| 4 | 8 studs | 16 nuts | 15.875 mm | 88.9 mm |
| 5 | 8 studs | 16 nuts | 19.05 mm | 95.25 mm |
| 6 | 8 studs | 16 nuts | 19.05 mm | 101.6 mm |
| 8 | 8 studs | 16 nuts | 19.05 mm | 107.95 mm |
| 10 | 12 studs | 24 nuts | 22.225 mm | 114.3 mm |
| 12 | 12 studs | 24 nuts | 22.225 mm | 120.65 mm |
| 14 | 12 studs | 24 nuts | 25.4 mm | 133.35 mm |
| 16 | 16 studs | 32 nuts | 25.4 mm | 133.35 mm |
| 18 | 16 studs | 32 nuts | 28.575 mm | 146.05 mm |
| 20 | 20 studs | 40 nuts | 28.575 mm | 158.75 mm |
| 22 | 20 studs | 40 nuts | 31.75 mm | 171.45 mm |
| 24 | 20 studs | 40 nuts | 31.75 mm | 171.45 mm |
| NPS (in) | RTJ stud length |
|---|---|
| 0.5 | Not listed |
| 0.75 | Not listed |
| 1 | 76.2 mm |
| 1.25 | 82.55 mm |
| 1.5 | 82.55 mm |
| 2 | 95.25 mm |
| 2.5 | 101.6 mm |
| 3 | 101.6 mm |
| 3.5 | 101.6 mm |
| 4 | 101.6 mm |
| 5 | 107.95 mm |
| 6 | 114.3 mm |
| 8 | 120.65 mm |
| 10 | 127 mm |
| 12 | 133.35 mm |
| 14 | 146.05 mm |
| 16 | 146.05 mm |
| 18 | 158.75 mm |
| 20 | 171.45 mm |
| 22 | 184.15 mm |
| 24 | 184.15 mm |
Reference sources
- https://texasflange.com/products/flange-dims-weights/bolt-and-stud-dimensions-asme-b16-5-flanges/
- https://apiint.com/flange-dimensions/bolt-stud-torque-charts/ansi-asme-b16-5-bolt-chart/
- https://m2prod.fastorq.com/media/media-download/menu/FASTORQ-Bolt-Specs-for-Standard-ANSI-Flanges.pdf
- https://datatool.pumps.org/piping-materials-iv/flanges
- https://www.asc-es.com/resource/Pipe%2BFitters%2BHandbook
- https://www.lamons.com/wp-content/uploads/2021/09/Lamons-Gasket-Fastener-Handbook.pdf
Prepare a bulk enquiry for delivery within India
Include the material grade, standard and edition, complete size, quantity, finish, certificates, required date and delivery PIN code. For valves include body/trim, seats, service fluid, temperature, end connection and actuator. For fasteners include thread, pitch, length, property class and coating.
For a village, small town or large city, give the district, nearest transport depot and unloading arrangements. Stock, suitability, freight and delivery are confirmed for each order.
Prepare your material enquiry Delivery checklistCommon questions
Are every size and class combination available?
No. The charts preserve the published combinations and label manufacturer specials or conflicts. “Not listed” is not a zero dimension and is not permission to interpolate a missing size.
Are inch fasteners interchangeable with converted metric sizes?
No. Converting an inch diameter for display does not change its thread series or fit. Order the specified thread, pitch or TPI, tolerance class, length convention and material.
What should a bulk buyer send for a quotation?
Send the exact standard and edition, grade or class, complete dimensions, quantity, finish, certification and delivery town, district and PIN code. Include the nearest transport depot for village or small-town delivery. Availability, price, freight and delivery are confirmed against your enquiry.
Reference sources and corrections · Toolkit terms. Source scope, units and missing values remain part of every reference. A catalogue listing is not a stock guarantee, approval for substitution or brand affiliation.