The standard series of rivet pitch (spacing) for pneumatic riveting guns is generally: 12.5, 15, 17.5, 20, 25, 30, 35, 40, 50, and 60 mm.
The arrangement pattern of rivets at component joints should be determined based on the strength requirements of the connecting members. Single-row riveting is used for general areas; for critical load-bearing areas where double-row or multi-row riveting is employed, the arrangement may be designed as either a parallel pattern or a staggered pattern.
When the rivet arrangement is designed as a single row or a double parallel row, the rivet pitch *S* should be no less than 3 times the rivet shank diameter. When rivets are arranged in a staggered pattern, the diagonal pitch *C* should be no less than 3.5 times the rivet shank diameter. To ensure a tight connection between components, the maximum rivet pitch should not exceed 8 times the rivet shank diameter; generally, the row pitch *A* should be no less than 3 times the rivet shank diameter.
For metal structural components, the minimum edge distance *c* of a rivet should be no less than 2 times the rivet diameter *d*; otherwise, this may lead to the formation of cracks along the component's edge, material bulging, and a reduction in structural strength. For composite structural components, the minimum rivet edge distance should be no less than 3 times the rivet diameter.
For rivets located near recesses or fillets, the distance *a* from the axis of the rivet hole to the recess or fillet area should be no less than half the diameter of the rivet head (or the formed head).
On a single riveted component, the variety of rivet specifications should be minimized whenever possible, and the rivet pitch should be standardized. For riveted assemblies with varying stack-up thicknesses, rivet specifications should be standardized by zone. Standardizing rivet patterns improves the efficiency of drilling and riveting equipment, reduces the variety of riveting machinery required, decreases the quantity of process tooling, shortens the time spent on setup adjustments and auxiliary tasks during riveting operations, and prevents frequent equipment shutdowns and tooling changeovers.
