There are several formulas for calculating rivet lengths in mechanical design manuals, but the following formula is generally used:
L=1.12×δ+1.4×d
Where d is the diameter of the rivet and δ is the thickness of the joint.
However, in actual riveting processes, it has been found that the length calculated using this formula is too long due to two reasons:
1. Determined by riveting equipment. Manual riveting tools use hydraulic power, which makes the riveting process relatively slow (while foreign riveting processes are considered fast). In addition, the composite board is relatively soft, so it is easy to produce distortion.
2. According to the rules of the mechanical design manual, if the rivet diameter is 6.3, the drilling diameter should be 6.7. However, the company's riveting equipment cannot perform such riveting, and a 6.3 hole size must be used.
Therefore, the formula for calculating rivet lengths should be:
l=δ+1.4×d
A. Total length of semi-tubular rivet shank with hemispherical head = 1.65 ~ 1.7d + L + 10% of the total plate thickness.
B. Total length of semi-sunk rivet shank with hemispherical head = 1.1d + L + 10% of total plate thickness.
C. Total length of the shank of the hemispherical head sunk rivet = 0.8d + L + 10% of the total plate thickness.
where d is the diameter of the rivet and L is the total thickness of the plate. Both d and L are in millimeters.
