The ASME B18.6.4 standard is an American National Standard that provides general and dimensional data for thread-forming and thread-cutting tapping screws metallic drive screws in the inch series. The American Society of Mechanical Engineers - ASME Originally issued as a separate standard, B18.6.4-1998 (reaffirmed in 2005) was consolidated into ASME B18.6.3 in 2013, which now covers machine screws alongside tapping and drive screws. The American Society of Mechanical Engineers - ASME Scope and Technical Contents The standard specifies requirements for several fastener types designed to create their own threads in metal, wood, or plastic. Key technical areas include: Fasteners Clearing House Fastener Types Thread-Forming Screws : Displace material to form a thread (e.g., Types A, AB, B). Thread-Cutting Screws : Remove material to cut a thread (e.g., Types 1, 23, 25, F). Metallic Drive Screws (Type U) : Unslotted screws hammered into pre-drilled holes, often for tamper resistance or masonry. Head Configurations : Covers flat countersunk (82° and 100°), oval, pan, fillister, hex, and truss heads. Some styles, like the Truss Head , are noted as "not recommended for new designs" due to inherent weakness. Drive Systems : Dimensions for slotted and recessed drives, including Phillips (Type I), Frearson (Type IA), and Square (Type III) recesses. Appendices : Provide critical engineering data such as: Approximate hole sizes for various materials. Instructions for protrusion and wobble gaging. Formulas used to derive the dimensional tables. The American Society of Mechanical Engineers - ASME Material and Performance Specifications : Commonly manufactured from (quenched and tempered to specific hardness), 300-series stainless steel (for corrosion resistance), and occasionally brass or nylon. Heat Treatment : Screws must typically be quenched and then tempered at a minimum of for at least one hour to reach required tensile and yield properties. : Available in various coatings including zinc (clear, yellow, black), black oxide, cadmium, and multi-layer ceramic topcoats like Accessing the Standard As a copyrighted document from the American Society of Mechanical Engineers (ASME) , the full PDF is generally a paid resource. You can find official copies or authorized abstracts through: Open Access - ASME
The ASME B18.6.4 standard defines the dimensional and performance requirements for tapping screws and metallic drive screws in the United States. While many older technical documents still refer to it, users should note that this standard was officially consolidated into ASME B18.6.3 to streamline fastener specifications. 🔩 Scope and Purpose ASME B18.6.4 covers "Inch Series" fasteners used to create their own mating threads in materials like sheet metal, plastic, and plywood. It provides: Dimensional Data : Head diameters, slot depths, and thread pitches. Performance Standards : Torsional strength, core hardness, and case depth. Gaging Instructions : Methods for measuring protrusion, wobble, and penetration of different head types. 📏 Common Screw Types The standard categorizes screws based on how they interact with the material: Thread-Forming (Types AB, B, BP, U) : Displace material to form a thread; often used in thin metal or plastics. Thread-Cutting (Types D, F, G, T) : Have flutes or slots to cut a thread, similar to a tap; used in heavier metals. Metallic Drive Screws (Type U) : Multiple-start threads designed to be hammered into pre-drilled holes for permanent or tamper-resistant joints. ⚠️ Status Update: Consolidation As of 2013 , the ASME B18.6 subcommittee combined B18.6.4 (Tapping Screws) and B18.6.3 (Machine Screws) into a single document. Why? Over 50% of the content was identical. Current Standard : ASME B18.6.3-2024 is the most up-to-date version for these fasteners. 📄 How to Access the PDF Official copies are available through authorized distributors: ASME Direct : Purchase the latest consolidated standard. ANSI Webstore : Access the 1998 (R2005) historical version. Intertek Inform : Provides the full publication in PDF format for technical reference. Thread Forming and Thread Cutting Tapping Screws and Metallic Drive Screws Inch Series | 1998 | Print Book | ASME
Note: While you searched for "b1864," the correct standard designation is ASME B18.6.4 . This content covers the correct standard regarding machine screws and tapping screws.
Topic: ASME B18.6.4 - Machine Screws, Tapping Screws, and Metallic Drive Screws 1. Executive Summary ASME B18.6.4 is the recognized American National Standard that covers the dimensional and general data for the most commonly used machine screws, tapping screws, and metallic drive screws. Published by the American Society of Mechanical Engineers (ASME), this standard is essential for mechanical engineers, manufacturers, and quality control inspectors to ensure interchangeability and proper fit in threaded fastener applications. 2. Scope and Application The standard defines the requirements for several types of screws used in various assembly operations: asme b1864 pdf
Machine Screws: Screws designed for insertion into pre-tapped holes or used with nuts. Tapping Screws: Screws that create their own internal threads when driven into a preformed hole (including Types AB, B, A, C, D, F, G, T, BF, and BT). Metallic Drive Screws: Screws driven into a material by pressure/impact, usually without pre-drilling or rotation.
Key Inclusions:
Dimensional data (diameters, lengths, head heights). General dimensional data for head styles. Thread dimensions and tolerances. Recommended hole sizes for tapping screws. The ASME B18
3. Key Head Styles Covered ASME B18.6.4 provides detailed dimensions for a wide variety of driving recesses and head shapes, ensuring that tools fit correctly. A. Head Shapes
Flat Countersunk Heads: Designed to sit flush with the surface. Oval Countersunk Heads: Similar to flat heads but with a decorative rounded top. Pan Heads: Slightly rounded heads with vertical sides. Truss Heads: Extra-wide, low-profile heads for covering larger holes. Round Heads: (Largely obsolete but still referenced for legacy designs) Fully spherical tops. Hex Heads: Hexagonal heads for wrench tightening. Hex Washer Heads: Hex heads with an attached washer flange. Binding Heads: Similar to pan heads but with a deeper undercut, often used for electrical connections. Fillister Heads: Cylindrical with a slightly rounded top and high profile.
B. Driving Recesses
Slotted: The traditional single-slot drive. Cross Recessed: (Phillips Drive) Cruciform shape. Type I Cross Recess: Standard Phillips. Type IA Cross Recess: Modified Phillips (often for longer life). Type II Cross Recess: Specific dimensional variations.
4. Thread Dimensions and Types One of the most critical aspects of ASME B18.6.4 is the classification of thread types for Tapping Screws. Tapping Screw Types