Rivets are described according to:
Solid shank rivets are the type commonly used for most purposes in sheetmetal work.
Sizes of rivets
Tinners' rivets are made of soft steel, coated with tin to prevent rusting. Sizes are given in ounces or pounds according to the weight of 1000 of the rivets. Thus, they may be 8 ounces (very small), 1 pound, or 1 1/2 pounds in size. Other kinds of soft-steel 'rivets are sized by diameter and length of shank, as 1/8” x 1/2" or 1/8” x 3/4" .
The length of all rivets except the flathead type is measured from the underside of the head to the end of the shank. The length of flathead rivets is over-all, that is, from the top of the head to the end of the shank.
First properly locate and punch or drill the rivet holes in the work. Decide on the proper type and size of rivet to be used. The length should equal the thickness of the stock plus 1 1/2 times the diameter of the rivet. The diameter of the rivet should be just sufficient to fit the hole as perfectly as possible. If the rivet is not long enough, too little metal will protrude for driving. As a result, just a little strain will be enough to separate the metals that were intended to be held securely and permanently in place by the rivet.
A rivet is secured in place by upsetting the end of the shank, that is, by mushrooming or spreading out the end with a hammer. If too much of the shank protrudes the rivet will bend, a tight clamp will not be made, or both may happen.
Insert the rivet in the hole so that the head is under the work resting on a solid surface such as an anvil, stake, or riveting blank. Hold the pieces of metal together firmly. If this is not done after the rivet is upset and headed, it may be found that the two metals have separated just at the spot where they were supposed to be kept in close contact by the rivet.
With a peen hammer, strike straight down on the rivet with a heavy blow. Then strike three or four times more with heavy blows. This will expand the shank of the rivet so that it completely fills the hole. Form a head by striking the outer edges of the upset rivet end with glancing blows, gradually circling the rivet. The peen hall or the face of the hammer may be used for this.
If the head must be formed to shape, a rivet header, or rivet set, should be used. Before peening the rivet end, the hole in the bottom of the rivet header is sometimes placed over the rivet and the header is struck with the hammer to force the pieces of metal together.
When riveting leather and similar soft materials, flathead copper rivets should be used. Burs should be placed over the end of these rivets before heading them.
A special tool is needed with Riv-Nuts. The tool is screwed on to the threaded part of the Riv-Nut; then compression is applied. This causes the Riv-Nut to bulge directly under the head. A key fitting into a slot cut into the metal on the underside of the head prevents the Riv-Nut from turning.
Though rivets are used for permanent fastenings, sometimes they must be removed, as for repairs. Several methods are used.
In all three cases, after the head of the rivet has been removed, drive the rivet out with a tool called a driving punch. This tool resembles a center punch but has no point on its end. Instead, it is ground flat. The diameter of this flat end should be slightly less than the diameter of the rivet. Never use a center punch because the point will spread the shank of the rivet and lock it in the hole.
In double-countersunk rivets, both head and upset ends are flush with the surface. These rivets may be removed by cutting a slot similar to the slot in a screw. This slot may be cut in either the head or the upset end. To cut this slot, use a small cape chisel. The edge of this cape chisel should be as wide as or a little wider than the diameter of the shank of the rivet.
Start the cut at the approximate center of the rivet and cut toward one edge. Then, using the same starting point, make a cut reaching to the opposite edge. There will now be a high point in the slot, at the center. Chip this out and then deepen the slot until the shank of the rivet is reached. When this occurs what is left of the head will f all off. By using the drift punch the rivet may now be removed.
When a rivet works loose it may indicate faulty workmanship, material or design. Try to find the cause. Possibly some other part has loosened and overloaded the rivet. It is good practice to replace a loose rivet, and safety regulations generally require that this be done. But if necessary, a rivet can be tightened by repeating the process used in installing it. A center punch may be used to spread it and cause its shank to fill the hole if the sections it holds together are thin. Remember that for a good job the rivet should be replaced, because the treatment used in retightening may so weaken it that it cannot be relied upon.