Rivets and Riveted Joint Design: Cone Head and Pan Head Impressions

Cone Head and Pan Head Impressions

ANSI Small Solid Rivets — ANSI/ASME B18.1.1-1972 (R1995)

Small solid rivets cover the range below 1/2-inch diameter and are used extensively in machine assemblies, light structural work, and specialty applications. All dimensions in inches.

Head Proportion Formulas (Small Solid Rivets)

Manufacturing Notes

• Heads are not machined or trimmed — circumference may be somewhat irregular; edges may be rounded or flat
• Rivets other than countersunk types have a fillet under the head not exceeding 10% of max shank diameter or 0.030 inch, whichever is smaller
• Unless otherwise specified, rivets have plain sheared ends at right angles within 2° to the axis
• Standard header points available when specified
• Material: ASTM A31 Grade A steel, or SAE J430 Grade 0; other materials when specified
• Length tolerance: ±0.016 inch for all small solid rivets

Shank Diameter Tolerances (Small Solid Rivets)

Truss Head Rivet Dimensions (inches)

Tinners Rivets (inches)

Size numbers refer to the approximate weight of 1000 rivets.

Belt Rivets (inches)

Size numbers refer to Stub's iron wire gage number. Length tolerance: +0.031, −0.000 inch.

Metric Small Solid Rivets — ANSI/ASME B18.1.3M-1983 (R1995)

This standard provides data for small solid rivets with flat, round, and flat countersunk heads in metric dimensions.

Main Series (Preferred) — Body Diameters (mm)

1.6, 2, 2.5, 3, 4, 5, 6, 8, 10, 12

Secondary Series (Nonpreferred) — Body Diameters (mm)

1, 1.2, 1.4, 3.5, 7, 9, 11

British Standard Small Rivets — BS 641:1951

Dimensions for small rivets for general purposes. All dimensions in inches.

Head Type Formulas (BS 641)

BS 641 Small Rivet Dimensions (inches)

Materials available: Mild steel, copper, brass, and a range of aluminum alloys and pure aluminum per BS 1473.

British Standard Rivets (1/2 to 1-3/4 inch) — BS 275:1927

Status: Obsolescent. Does not apply to boiler rivets.

Key definitions in this standard:

• "Nominal diameter" and "standard diameter" are synonymous
• "Tolerance" refers to variation from nominal diameter — not the difference between under-head and near-point diameters

Shank Diameter Tolerances (BS 275)

Tolerances are measured at three positions:

• Position X: Under the head
• Position Y: At 1/2D from end (for rivets 5D long or under) or 4-1/2D from head (for longer rivets)
• Position Z: At 1/2D from end (only for rivets longer than 5D)

Note: Sizes 9/16, 11/16, 13/16, 15/16, 1-1/16, 1-3/16, 1-5/16, 1-7/16, 1-9/16, and 1-11/16 are available but should be dispensed with wherever possible (per BSI recommendation).

British Standard Rivets for General Engineering — BS 4620:1970

Based on ISO Recommendation ISO/R 1051. All dimensions in millimeters. Snap head rivet dimensions of 14 mm and above are taken from German Standard DIN 124.

Key Definitions (BS 4620)

Manufacturing Requirements

• The radius under the head shall run smoothly into the face of the head and shank without step or discontinuity
• Made by cold or hot forging from mild steel, copper, brass, pure aluminum, aluminum alloys, or other suitable metal

Hot Forged Rivets (BS 4620) — Dimensions in mm

Sizes in parentheses are nonpreferred.

Cold Forged Rivets (BS 4620) — Dimensions in mm

Note: Cold forged flat heads are not available above 12 mm diameter.

Tentative Range of Preferred Nominal Lengths — BS 4620

All dimensions in millimeters. Sizes and lengths in parentheses are nonpreferred and should be avoided. An "X" indicates the length is available for that shank diameter.

Small Diameters (1 mm to 6 mm)

Medium Diameters (8 mm to 16 mm)

Large Diameters (20 mm to 36 mm)

Quick-Reference: Rivet Selection Decision Matrix

When the practitioner the practitioner trained new engineers at her firm, she always started them with a decision framework. Not formulas—decisions. Here's the matrix she used:

What the practitioner Learned — And What You Should Remember

Six months after her bridge inspection, the practitioner the practitioner presented her findings at a regional engineering conference. Her closing slide contained three bullet points:

1. The joint is only as strong as its weakest failure mode. You don't design a riveted connection by calculating one number. You calculate every possible failure mode and the joint strength equals the lowest value. The examples in this guide prove it — shear, bearing, and tension each governed different joints.

2. Dimensions are not suggestions. Every tolerance in this guide exists because someone, somewhere, learned the hard way what happens when a rivet is 0.06 inches too long or a hole is 1/16 inch too small. The ANSI, ASME, and BS standards represent decades of accumulated failure analysis.

3. The best fastener is the one you understand completely. Rivets have been largely replaced by high-strength bolts and welding in new construction. But millions of riveted structures remain in service worldwide. And in specialized applications — aircraft, thin-plate assemblies, vibration-sensitive joints — rivets remain the optimal permanent fastener. Understanding their engineering is not historical curiosity. It's professional competence.

Your Next Step

Pull up the last riveted joint you designed, inspected, or encountered. Run through the failure mode analysis from this guide. Calculate the efficiency. Compare it against the AISC or ASME allowable stresses.

Then ask yourself the question the practitioner asked every new engineer on her team:

"Do you know which failure mode governs this joint — or are you just hoping it holds?"

If you can answer with a number, you're an engineer. If you can't, you now have every tool you need to become one.

This guide covers structural and machine-member riveted joints per ANSI B18.1.2-1972 (R1995), ANSI/ASME B18.1.1-1972 (R1995), ANSI/ASME B18.1.3M-1983 (R1995), BS 275:1927, BS 641:1951, and BS 4620:1970. For pressure vessel riveting, consult the ASME Boiler and Pressure Vessel Code directly.