A working rivet is one which has movement under structural stress, but
has not loosened to the extent that movement can be observed. This
condition can sometimes be detected by a dark, greasy residue or
Where possible, the rivets used in repair are to be the same type as those used in the original
The rivet code designation gives the type of rivet, the material, the diameter in 1/32 of an inch, and the
length in 1/16 of an inch.
The determination of the length of a rivet is an important part of any repair. The length used depends on
the grip or combined thickness of material to be riveted plus a minimum allowance of 1/2 diameter for
upsetting the shank.
The nearest standard rivet length greater than the calculated sum is always used.
There are specific considerations in laying out the rivet pattern for a repair; however, there are some rules
which will apply generally in all instances.
When possible, rivet edge distance, rivet spacing, and distance between rows should be the same as that
of the original installation.
When new sections are to be added, the edge distance measured from the center of the rivet should
never be less than two times the diameter of the shank. The distance between rivets or pitch should be at
least three times the diameter; and the distance between rivet rows should never be less than 2 1/2 times
Mark the rivet pattern on the metal with a soft pencil to avoid scratching.
Rivet holes may be drilled with either a light power drill or a hand drill. The standard shank twist drill is
most commonly used.
Before drilling, center punch all rivet locations. The center punch mark should be large enough to prevent
the drill from slipping out of position.
Place drill in center punched mark. When using power drill, rotate bit a few turns by hand before starting
motor. While drilling, always hold drill at a 90 degree angle to work.
Avoid excessive pressure; let the drill do the cutting. Never push drill through stock. Remove all burrs with
a metal countersink or file.
Accomplish transfer of holes from drilled part to another part by placing second part over first and using
established holes as a guide.