Learn how to read an aircraft rivet size chart, decode dash numbers, choose diameter and length, and check hole and shop-head dimensions.
To use an aircraft rivet size chart, match the specified rivet standard, head style and alloy first. Read the diameter and length codes, compare them with the material grip and required protrusion, then check the hole and finished shop-head limits. In real-world aviation, approved aircraft data always overrides a generic chart.
In our Aviation & Real-World Flying reference, we are dealing mainly with solid-shank rivets in sheet-metal structures. Sheet alloy, thickness and joint design all matter; our overview of materials used in aircraft structures explains why apparently similar skins and supporting members are not necessarily interchangeable.
How do you read an aircraft rivet chart?
- Find the controlling specification. Start with the aircraft drawing, structural repair manual or other approved maintenance data. Check that the chart uses the same rivet standard and measurement system.
- Match the rivet family. Identify whether it is solid or blind, its head style, material or alloy code, and any special condition. A universal-head aluminium rivet cannot automatically replace a countersunk or different-alloy rivet.
- Decode diameter and length. Common AN/MS solid-rivet designations express diameter in thirty-seconds of an inch and length in sixteenths, but metric and proprietary systems use different conventions.
- Measure the grip. Add the thickness of every member being fastened. Gaps should be corrected rather than counted as legitimate grip.
- Check the installation dimensions. Use the chart's specified hole limits, edge distance, spacing, pre-drive protrusion and finished shop-head dimensions.
- Inspect the complete joint. A dimensional gauge does not excuse a tipped head, cracked countersink, clinched shank, loose sheet or damaged factory head.
What do aircraft rivet dash numbers mean?
For a common designation such as MS20470AD4-5, MS20470 identifies a universal-head solid rivet standard, AD denotes 2117 aluminium alloy, 4 means 4/32 inch diameter, or 1/8 inch, and 5 means 5/16 inch length. Older AN-style references are also found on drawings and charts.
| Chart field | What it tells you | Frequent mistake |
|---|---|---|
| Diameter | Nominal shank diameter; often coded in 1/32-inch increments | Reading the number as sixteenths |
| Length | Rivet length; commonly coded in 1/16-inch increments | Confusing length with grip |
| Head style | Universal, countersunk or another specified profile | Substituting a head that happens to fit the hole |
| Alloy or material | Fastener material and, in some systems, its condition | Choosing by colour or appearance alone |
| Hole size | Permitted finished-hole diameter or recommended tooling | Assuming a drill number guarantees the final hole size |
| Edge distance | Distance from the hole centre to the material edge | Measuring from the side of the hole |
| Shop head | Required driven-head height and diameter | Treating nominal dimensions as universal rejection limits |
Length is measured from beneath the factory head on most protruding-head rivets. A countersunk rivet is normally measured over its full length, including the head. Always confirm this in the applicable standard rather than transferring one convention to every fastener family.
How is rivet length chosen from material grip?
For a conventional solid rivet, a common preliminary rule is L = G + 1.5D, where L is rivet length, G is total material grip and D is shank diameter. The extra shank forms the shop head.
For example, a 1/8-inch-diameter rivet passing through a 1/8-inch stack gives a preliminary length of 1/8 plus 3/16, or 5/16 inch. That corresponds to a -5 length under the usual inch-based convention. The chart and approved repair data must still confirm the selection.
Do not automatically round to the next substantially longer rivet. Excess length encourages the shank to bend or clinch; insufficient length produces an undersized shop head. Dimpled joints, deep countersinks, sealant and unusual head forms may need the dedicated selection table rather than the simple formula.
Can a chart tell you which rivet diameter to use?
A rivet size chart is a dimensional reference, not a structural design calculation. Diameter must come from the drawing or approved repair scheme because joint shear, sheet bearing, fatigue, pitch, edge distance and load direction all affect the required fastener.
The familiar rule that rivet diameter should be about three times the thickest sheet is only a workshop estimate, not authority to alter an aircraft structure. Aircraft load factor is also a separate quantity; our explanation of how load-factor charts describe G and structural loading should not be converted directly into a rivet diameter.
Likewise, do not install the next diameter merely because an existing hole is enlarged. An approved oversize repair may require controlled reaming and a particular fastener while preserving edge distance and countersink limits. In other cases, the damaged hole requires a different repair altogether.
How do you check the rivet after driving?
Compare the driven shop head with the dimensions or gauge specified by the applicable chart. For many conventional solid rivets, the familiar nominal target is approximately 1.5D across and 0.5D high, but approved data supplies the actual acceptable range.
Then inspect the whole installation: the factory head should be seated, the sheets should be tightly clamped, and the shop head should not be tipped, split or folded. Check for scratches, cracks around a countersink, an elongated hole and tool marks such as a rivet-gun “smile”. A shop head can pass a gauge while the joint remains defective.
Does the same chart apply to blind rivets?
No. Blind rivets are selected by their exact fastener specification, diameter, approved grip range, head, material and stem or locking system. Their grip-range number must not be interpreted as though it were the length dash number of an AN/MS solid rivet.
Structural blind fasteners are not generic substitutes for solid rivets. On a certificated aircraft, use the specified maintenance data and have the work performed and released by people authorised under the applicable regulations.