Semi-tubular rivets (also known as tubular rivets) are similar to solid rivets, except they have a partial hole (opposite the head) at the tip. The purpose of this hole is to reduce the amount of force needed for application by rolling the tubular portion outward. The force needed to apply a semi-tubular rivet is about 1/4 of the amount needed to apply a solid rivet. Tubular rivets can also be used as pivot points (a joint where movement is preferred) since the swelling of the rivet is only at the tail. Solid rivets expand radially and generally fill the hole limiting movement. The type of equipment used to apply semi-tubular rivets range from prototyping tools (less than $50) to fully automated systems. Typical installation tools (from lowest to highest price) are hand set, manual squeezer, pneumatic squeezer, kick press, impact riveter, and finally PLC-controlled robotics. The most common machine is the impact riveter and the most common use of semi-tubular rivets is in lighting, brakes, ladders, binders, HVAC duct work, mechanical products, and electronics. They are offered from 1/16-inch (1.6 mm) to 3/8-inch (9.5 mm) in diameter (other sizes are considered highly special) and can be up to 8 inches (203 mm) long. A wide variety of materials and platings are available, most common base metals are steel, brass, copper, stainless, aluminum and most common platings are zinc, nickel, brass, tin. All tubular rivets are waxed to facilitate proper assembly. The finished look of a tubular rivet will have a head on one side, with a rolled over and exposed shallow blind hole on the other. Semi-tubular rivets are the fastest way to rivet in mass production but require a capital investment.
What length to use?
1. View the chart below.
2. Find the body diameter you are using. (the D dimension)
3. All the way to the right of the graph you will find a "suggested clinch allowance. Add that number to the total thickness you are looking for. That is the "approximate length you will need.
example: If you are using a 1/4 body diameter, than add .157 to your total thickness. This will be the approximate length you need.