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Aircraft Rivet Calculator

Step-by-step tool to determine the minimum rivet diameter and required rivet length for sheet metal repairs. Supports both inches and millimeters. Used by aircraft mechanics for structural repairs and modifications.


Rivet Calculator

Input Requirements: Enter thickness measurements in the selected unit. Calculator will determine minimum rivet specifications per industry standards.

Rivet Calculation Guidelines

Follow these industry-standard formulas for structural rivet sizing:

Minimum Rivet Diameter
Minimum Diameter = 3 × Thickness of Thickest Plate

Ensures adequate shear strength for the joint

Required Rivet Length
Required Length = Clamping Thickness + (1.5 × Rivet Diameter)

Provides proper shop head formation (1.5D protrusion)

Industry Standards for Rivet Spacing

Select material type to determine proper rivet spacing and edge distance:

Material Spacing Rule Edge Distance Rule
Aluminum 4 × Rivet Diameter 2 × Rivet Diameter
Steel 4.5 × Rivet Diameter 2.5 × Rivet Diameter
Composite 5 × Rivet Diameter 3 × Rivet Diameter

Source: FAA AC 43.13-1B, Aircraft Structural Repair Manual (SRM).

Rivet Layout & Repair FAQ

Rivet Pitch is the distance between the centers of adjacent rivets in the same row. If rivets are too close, the sheet metal may crack (zipper effect); if they are too far apart, the joint may buckle or lose structural integrity. The standard pitch is usually 4 to 6 times the rivet diameter (4D - 6D).

Edge distance is the space from the center of the rivet hole to the edge of the sheet. In aviation, the absolute minimum is usually 2 times the rivet diameter (2D). For example, for a 1/8" rivet, the center of the hole must be at least 1/4" from the edge to prevent the metal from tearing.

The general formula for rivet length is:
Length = Grip (total thickness of sheets) + (1.5 × Rivet Diameter).

The 1.5D extra length allows enough material to form a proper "shop head" (bucktail) that is 1.5D wide and 0.5D high.

In multi-row repairs (staggered or chain), Transverse Pitch is the distance between the centerlines of the rows. This is typically 75% of the rivet pitch. Proper row spacing ensures the load is distributed evenly across the repair patch.