ASME Screw Thread Standards Index — Complete B1 Series List with Scope Summaries
Complete index of the ASME B1 screw thread standards — unified inch (UN/UNR/UNJ), Acme and Stub Acme, buttress, metric M and MJ, pipe threads (NPT series, Dryseal, hose coupling), gaging and rounding-practice documents — with year, length and a one-line scope summary per document, transcribed row-for-row from the collected index.
Last updated: 2026-11
Specifications
Thread engineering questions usually start with "which B1 is this even in?" — and the answer matters because the documents interlock: B1.1 defines the unified UN/UNR form and its classes, B1.2 the gages that accept it, B1.3 the gaging systems that decide dimensional acceptability on the shop floor, B1.15 the UNJ aerospace variant with its rolled-thread radius, B1.13M the metric M profile and B1.21M its MJ aerospace counterpart, B1.20.1 the NPT-family pipe threads and B1.20.3 the Dryseal variant that seals without compound. The collected index lines up all 21 documents with year, printed length and a one-line scope — from B1.1-2003 (188 pages, unified inch UN & UNR) through the specialized ends of the series (B1.11 microscope objective threads; B1.12 Class 5 interference-fit; B1.9 buttress for unidirectional loads; B1.10M miniature threads 0.30–1.40 mm that extend below the 1.6 mm floor of the ISO/Unified series) to B1.30-2002, the rounding-and-calculation practice every other document quietly assumes. Reading it as a selection map: form documents (B1.1, B1.8, B1.9, B1.13M, B1.15, B1.21M), pipe documents (B1.20.x), gage documents (B1.2, B1.3, B1.16M, B1.20.5, B1.22M), and the practice document (B1.7 nomenclature, B1.30 rounding). The index's own advisory stands: it helps you pick the correct document — always consult the latest ASME publication for design, since several tabulated editions carry later revisions.
| Coverage | 21 ASME B1 documents: form standards (B1.1 UN/UNR, B1.8 Stub Acme, B1.9 Buttress, B1.10M miniature, B1.13M metric M, B1.15 UNJ, B1.21M metric MJ, B1.11 microscope objective, B1.12 Class 5 interference-fit), pipe threads (B1.20.1 NPT family, B1.20.2M metric, B1.20.3 Dryseal, B1.20.7 hose coupling), gaging (B1.2, B1.3, B1.16M, B1.20.5, B1.22M) and practice (B1.7 nomenclature, B1.30 rounding) |
|---|---|
| Per-document data | Designation with year, printed page count, full name, one-line scope summary — e.g. B1.1-2003, 188 pages, Unified Inch Screw Threads (UN & UNR Thread Form) |
| Gaging chain | B1.2 gages for UN/UNR; B1.3 gaging systems for dimensional acceptability (UN/UNR/UNJ and M/MJ); B1.16M gages for metric M; B1.20.5 gaging for Dryseal; B1.22M gages for MJ |
| Edition currency | Year column shows the tabulated edition; several documents carry later ASME revisions — consult the latest publication for design (source advisory, reproduced) |
| Standard | Pages | Year | Name | Summary |
|---|---|---|---|---|
| B1.1-2003 | 188 | 2003 | Unified Inch Screw Threads (UN & UNR Thread Form) | Defines form, series, classes, allowance, tolerances, and designation for unified screw threads. |
| B1.2-1983 | 179 | 1983 | Gages and Gaging for Unified Inch Screw Threads | Specifications and dimensions for thread gages and measuring equipment for UN/UNR threads. |
| B1.3-2007 | 20 | 2007 | Screw Thread Gaging Systems for Dimensional Acceptability — Inch & Metric (UN, UNR, UNJ, M, MJ) | Gaging systems for determining acceptability of UN/UNR/UNJ and metric M/MJ threads (internal & external). |
| B1.5-1997 | 124 | 1997 | Acme Screw Threads | General purpose and centralizing Acme threads (single-start; also guidance for multiple-start if suitable). |
| B1.7-2006 | 36 | 2006 | Screw Threads: Nomenclature, Definitions, and Letter Symbols | Uniform practice for screw thread terms and symbols for drawings, tables, and formulae. |
| B1.8-1988 | 30 | 1988 | Stub Acme Screw Threads | Coarse-pitch, shallow depth threads for special applications constrained by mechanics or metallurgy. |
| B1.9-1973 | 21 | 1973 | Buttress Inch Screw Threads (7°/45°), 0.6p Basic Height | Buttress form threads for unidirectional loads; geometry and engagement height specified. |
| B1.10M-2004 | 24 | 2004 | Unified Miniature Screw Threads | Miniature threads 0.30–1.40 mm; extends below ISO/Unified series that start at 1.6 mm. |
| B1.11-1958 (rev. 2011) | 9 | 2011 | Microscope Objective Thread | Mounting thread for objective assemblies to microscope bodies/turrets. |
| B1.12-1987 | 56 | 1987 | Class 5 Interference-Fit Thread | Plastic-flow interference-fit (Class 5) threads, modified National form, coarse series, 0.250–1.500 in. |
| B1.13M-2005 | 16 | 2005 | Metric Screw Threads: M Profile | General metric 60° symmetrical M-profile (ISO 68-1 base) — form and general data. |
| B1.15-1995 | 72 | 1995 | Unified Inch Screw Threads (UNJ Thread Form) | UNJ profile, designations, diameter-pitch series (0.600–6.000 in), limits and tolerances. |
| B1.16M-1984 | 164 | 1984 | Gages and Gaging for Metric M Screw Threads | Specifications/dimensions for gages and measuring equipment for M series metric threads. |
| B1.20.1-2013 | 40 | 2013 | Pipe Threads, General Purpose, Inch | Dimensions and gaging for NPT, NPSC, NPTR, NPSM, NPSL series. |
| B1.20.2M-2006 | 28 | 2006 | Pipe Threads, 60° General Purpose (Metric) | Metric conversion of ASME B1.20.1 (NPT) for general purpose pipe threads. |
| B1.20.3-1976 | 19 | 1976 | Dryseal Pipe Threads, Inch | Modified American pipe threads designed to seal pressure-tight joints without sealing compounds. |
| B1.20.5-1991 | 59 | 1991 | Gaging for Dryseal Pipe Threads — Inch | Practical inspection methods and commonly used gages for production evaluation of Dryseal pipe threads. |
| B1.20.7-1991 | 14 | 1991 | Hose Coupling Screw Threads, Inch | Threads for hose couplings, valves, nozzles, and fittings (½ to 4 in common sizes). |
| B1.21M-1997 | 64 | 1997 | Metric Screw Threads: MJ Profile | MJ profile for 1.6–200 mm; designations, diameter/pitch series, limits and tolerances. |
| B1.22M-1985 | 136 | 1985 | Gages and Gaging for MJ Metric Screw Threads | Specifications/dimensions for gages used on MJ metric threads and related measuring equipment. |
| B1.30-2002 | 32 | 2002 | Screw Threads: Standard Practice for Calculating & Rounding Dimensions | Uniform practices for calculating and rounding numeric values for inch/metric screw thread design dimensions. |
Materials
- Not applicable — reference index; the underlying thread dimensions live on this catalog's per-standard thread dimension pages
Ordering & documentation
Documents
Shipments are backed by Mill Test Certificate (MTC), Dimensional Report, Salt Spray Test Report on request, with full batch traceability from raw material to finished product. Quality management follows the owner-confirmed compliance list: ISO 9001:2015, RoHS, REACH. Exact document sets are confirmed on the order.
Quotation
- The fastener family (ASME Screw Thread Standards Index — Complete B1 Series List with Scope Summaries) plus the standard designation from your drawing — DIN / ISO / JIS / ASTM / ANSI, or a drawing for custom parts.
- Size (diameter and length), thread type (metric or inch), property class or grade, and coating or finish.
- Quantity per size and your target delivery date.
- Destination country, and any required documents (for example a mill test certificate) so the quote includes them.
Sample & supply
Minimum order quantity is 10,000 pieces. Stock items run 3–7 days. Quantities or variants outside the standard range are confirmed at quotation.
Storage & shipping
Parts are packed for export and shipped factory-direct to buyers in Europe, Asia, the Americas and the Middle East. Store fasteners dry and protected until installation, and keep coated parts in their packaging until use; specific packing and preservation requirements can be stated on the order and confirmed at quotation.
Frequently asked questions
How do I use this index to route a thread question to the right standard, and why do the gage documents matter as much as the form documents?
Route by what you are holding: a unified inch thread (UNC 1/4-20 style) is B1.1 for form, series and classes, with B1.2 supplying the GO/NO-GO gage dimensions and B1.3 defining how gaging decides acceptability — three documents, one thread. A metric M thread is B1.13M (form) and B1.16M (gages); its aerospace MJ counterpart is B1.21M with B1.22M gages. Pipe threads: NPT and its straight relatives (NPSC/NPTR/NPSM/NPSL) are B1.20.1, the metric conversion B1.20.2M, Dryseal B1.20.3 with gaging in B1.20.5. The special forms have their own documents — Acme B1.5, Stub Acme B1.8, buttress B1.9, miniature B1.10M (0.30–1.40 mm, below the 1.6 mm floor where the ISO/Unified series starts), UNJ aerospace B1.15, even B1.11 for microscope objective threads. Why the gage documents matter: a form standard tells you what perfect is, but production threads are accepted by gaging, and using a B1.1 thread with the wrong gage practice (or a worn gage set outside B1.2 limits) passes bad threads and rejects good ones — the source's index deliberately lists the gage documents at full standing. Two practice documents underpin everything: B1.7 fixes nomenclature and letter symbols so drawings and tables mean the same thing, and B1.30 fixes how thread dimensions are calculated and rounded — the reason two shops computing the same B1.1 size get identical numbers. For current editions, go to ASME directly; the index's tabulated years are its advisory starting points.
What is the MOQ and lead time for threaded parts and tooling referenced by this chart?
The minimum order quantity is 10,000 pieces. Stock items ship in 3–7 days; non-stock items are confirmed at quotation. Confirm the exact schedule against quantity, size mix and any tooling items at quotation.
Related knowledge
- Thread-Forming vs Thread-Cutting vs Thread-Rolling Self-Tapping Screws: What the Evidence Settles on Base Material
- Screw Family Selection by Base Material: Wood, Machine and Self-Tapping Threads, Engagement and Coating
- Hex Bolts vs Socket Head Cap Screws: What the Evidence Settles on Strength, Clearance and Cost
Request a Quote
Get factory-direct pricing from the manufacturer.
What to include in your inquiry
- ✓ Standard and property class (e.g. DIN 912, ISO 4762, class 8.8) — or a drawing for custom parts.
- ✓ Sizes, lengths and thread type (metric or inch).
- ✓ Quantity per size and your target delivery date.
- ✓ Destination country, plus any coating or finish requirement.
- ✓ Any documents you need with the shipment (e.g. mill test certificate) so the quote includes them.
- ✓ Your inquiry goes straight to the factory team by email and gets a reply within 24 hours.
- ✓ Factory-direct pricing
- ✓ Standard and custom specifications
- ✓ Factory-direct export to buyers in Europe, Asia, the Americas and the Middle East
- ✓ Full fastener family support