Generally speaking, there are three kinds of rebar bending machines: hand powered, hydraulic, and electro-mechanical. The simplest machines, hand-powered hickey bars, are readily available and inexpensive. Hydraulic machines are slower and shorter-lived than electro-mechanical devices, but they are also less expensive. Manufacturers of large rebar bending machines build them to customer specifications, making each machine a little different. These giants are nearly always electro-mechanical.
The task at hand determines the nature of the rebar bending machine. For occasional use on smaller diameter rebar, a hickey bar is usually the best choice because of its low cost. A hickey bar is a simple lever arm — a long steel bar — with a slot or studs for grabbing the rebar at one end. Arm strength and body weight are used to apply force to the other end of the hickey bar to bend the rebar.
For a tight bend, two hickey bars can be used. These simple rebar bending machines can be used on rebar up to 5/8 inch (1.6 cm) in diameter. Hickey bars with cutting capability are also available.
To bend more than a few pieces of rebar, an electro-mechanical or hydraulic machine is a better choice. Some of the hydraulic machines are quite portable, weighing as little as 33 lbs (15 kg), and are designed to be held by hand. These machines are designed to bend rebar left exposed after concrete has been poured over a rebar web. Bends of up to 180 degrees are possible with these machines.
When the contractor is bending rebar in preparation for installation into a mold, larger machines are usually chosen. The larger bending machines are usually transported by truck, and usually will not leave the truck bed until the rebar is in place and the machine is returned to storage. These machines run on diesel fuel, enabling them to function on work sites that have no power supply.
Even large, on-site machines can handle rebar only up to 1.18 inches (30 mm) in diameter; larger diameters must be bent off site. The most powerful multipurpose, programmable rebar bending machines are large, fixed in place, and expensive. These are generally bolted into concrete floors in industrial buildings where they do both bending and cutting. Off-site rebar bending machines often double as pipe bending machines, but even these can only create bends of 180 degrees.