FAA Aviation Mechanic General (AMG)Materials, Hardware and ProcessesMedium
A technician is laying out a row of 1/8-inch (0.125 in) diameter universal head rivets along the edge of a 0.040-inch aluminum skin panel. Per standard sheet metal practice, what is the minimum acceptable edge distance from the center of the rivet hole to the edge of the sheet?
- A0.25 inch
- B0.125 inch
- C0.1875 inch
- D0.375 inch
Show answer & explanationAnswer & explanation
Correct answer: A. 0.25 inch
Standard practice calls for a minimum edge distance of two times the rivet shank diameter. For a 0.125-inch rivet: 2 × 0.125 = 0.25 inch. Less than this risks the sheet cracking or the rivet pulling through the edge.
Why the other options are wrong
- B. This equals only 1× diameter, well below the minimum.
- C. This is 1.5× diameter, still insufficient edge distance.
- D. This is 3× diameter, more than required (acceptable but not the minimum).
Rivet Edge Distance
The minimum distance from a rivet hole center to the sheet edge, typically 2 times the rivet shank diameter, to prevent edge cracking or rivet pull-through.
- Minimum edge distance = 2 × rivet diameter
- Applies to standard/universal head rivets
- Insufficient edge distance risks skin cracking under load
Memory trick: Two diameters from the edge keeps the rivet from a wedge (crack)