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ASME B18.17-1968 (1983) — Miniature Rivets
🔬 ASME B18.17-1968 (1983) (originally ANSI B18.17-1968) is the dedicated Standard in the ASME B18 fastener family for miniature solid rivets — solid rivets with shank diameters below the lower end of the conventional small-rivet range (typically under 1/8 inch) — extending B18.1.1 (Small Solid Rivets) into the subminiature size band. Miniature rivets are widely used in instruments, electrical contacts, relays, switches, optical assemblies, toys, and small mechanisms. They are lightweight and tiny, typically cold-headed from brass, copper, aluminum, low-carbon steel, or stainless steel, with copper alloys or precious-metal plating chosen for electrical applications requiring good conductivity and wear resistance.
💡 This article is written from domain knowledge of ASME B18.17. The available copy of the Standard is a scanned document without a text layer, so the content below is developed around the subject “miniature rivets”; specific dimensions and values are subject to the official text.
1. Scope and Product Positioning 📌
Rivets in the B18 system are graded by size: B18.1.1 covers small solid rivets, B18.1.2 covers large rivets of 1/2 inch nominal diameter and larger, and B18.17 addresses the still-smaller subminiature band required by precision instruments and electronic products. Unlike large rivets, which are typically hot-driven, miniature rivets are almost always cold-headed and assembled by press riveting or orbital riveting. The Standard defines head types, shank series, and head-proportion ratios to give a common basis for high-volume automated manufacturing and assembly.
⚠️ Miniature rivet shanks and head dimensions are measured in thousandths of an inch, so manufacturing and inspection precision far exceeds that of ordinary rivets. Verify the standardized head type and shank series when selecting, and confirm tooling and capacity with the manufacturer for non-standard sizes.
2. Technical Requirements and Material Selection 📏
| Head Type | Features | Typical Applications |
|---|---|---|
| Round / button head | Hemispherical top, flat bearing face | General instrument assembly |
| Flat head | Flush top, low profile | Space-constrained compact mechanisms |
| Flat countersunk head | Conical seat, head flush with surface | Panels and housings requiring smooth surfaces |
| Oval countersunk head | Countersunk seat with oval crown | Electrical contacts and precision enclosures |
| Typical Material | Characteristics | Applications |
|---|---|---|
| Brass / copper | Good conductivity, easy to head | Electrical contacts, switches, conductive joints |
| Aluminum | Lightweight, corrosion resistant | Lightweight structures, non-electrical joints |
| Low-carbon steel | Strong, economical | General mechanisms and mechanical joints |
| Stainless steel | Corrosion resistant, strong | Humid environments, precision instruments |
| Precious metal / plated | Low contact resistance, wear resistant | High-reliability electrical contacts |
The Standard controls head-proportion ratios (head diameter and height relative to shank diameter) to secure both strength and assembly appearance, with shank diameters graded in a series; head proportions apply to nonstandard shank diameters as well. Where the rivet head serves as a contact face, surface finish, plating uniformity, and material conductivity directly govern contact resistance stability and contact life.
⚠️ Miniature rivet quality depends closely on hole fit and press stroke control: an oversized hole yields an undersized formed head, while excessive stroke can crush the head or damage thin workpieces. Validate first articles and lock equipment parameters before volume production.
3. Engineering Practice Essentials 🛠️
- 🔍 Selection workflow: choose the head type by assembly space → select material by strength and conductivity needs → size the shank by material thickness and hole → verify head proportions → define surface finish.
- 🔧 Riveting process: miniature rivets are usually set by press riveting or orbital riveting, the latter being friendlier to thin-wall parts; high-volume lines favor vibratory bowl feeding with automatic riveting fixtures.
- ⚡ Contact design: where the head is an electrical contact, design head shape, plating, and finish against contact-life requirements, verifying with fretting and temperature-rise tests where necessary.
- 📋 Quality inspection: sample shank diameter, head dimensions, and formed-head fullness with magnifying or vision measurement systems to avoid missing micron-level defects by eye.
4. Frequently Asked Questions ❓
❓ Q: How does B18.17 relate to B18.1.1?
A: Both cover solid rivets, split by size: B18.1.1 covers small solid rivets, while B18.17 covers the still-smaller miniature band (shanks typically below 1/8 inch). Select the standard by shank diameter.
A: Both cover solid rivets, split by size: B18.1.1 covers small solid rivets, while B18.17 covers the still-smaller miniature band (shanks typically below 1/8 inch). Select the standard by shank diameter.
❓ Q: Why are miniature rivets often made of copper alloys?
A: Many miniature rivets serve in electrical contacts and conductive joints, and copper alloys such as brass combine good conductivity with easy heading; with precious-metal plating (e.g., silver) they deliver low, stable contact resistance for relays and switches.
A: Many miniature rivets serve in electrical contacts and conductive joints, and copper alloys such as brass combine good conductivity with easy heading; with precious-metal plating (e.g., silver) they deliver low, stable contact resistance for relays and switches.
🔍 Q: Is hot riveting suitable for miniature rivets?
A: Generally not. The tiny size makes heating difficult to control and risks damaging precision parts; industry practice is cold heading followed by press or orbital riveting. Hot riveting belongs to large structural riveting.
A: Generally not. The tiny size makes heating difficult to control and risks damaging precision parts; industry practice is cold heading followed by press or orbital riveting. Hot riveting belongs to large structural riveting.
❓ Q: Does the Standard cover tubular (semi-tubular) miniature rivets?
A: The miniature rivet system is based on solid rivets (as the Standard’s title indicates); semi-tubular and tubular rivets are mainly covered by the B18.7 series and the corresponding metric standards. Confirm the exact scope against the official text.
A: The miniature rivet system is based on solid rivets (as the Standard’s title indicates); semi-tubular and tubular rivets are mainly covered by the B18.7 series and the corresponding metric standards. Confirm the exact scope against the official text.
