From the time wires were first placed in protective pipes, electricians have been bending conduit to take cable where it needs to go. Early hand benders allowed pipe to be effectively bent without walls collapsing. Today, basic hand benders don’t look much different than those early models, but significant improvements have been made.
Several categories of benders are available. Mechanical benders are a step up from basic bending tools, hydraulic benders are available for rigid conduit, and electric benders shorten the time it takes to make multiple bends in the field. In addition, various methods are available for bending plastic conduit.
For years, two basic models were the hand-bender standards: Benfield models are made of iron with markings on the heads that provide reference points for bend angles, and Gardner-style benders are made of die-cast aluminum with built-in spirit levels at the 45-degree and 90-degree positions to help make accurate bends.
Damon Henderson, product manager, benders, Greenlee, said: “Repeatability of bends is very important for hand benders, so improvements have been made, enabling users to more easily achieve consistent bend angles. Angle markers and sight lines are design features that enable clear visibility toward achieving the desired bend.
“Hand benders have also become lighter while still maintaining durability.
“Aluminum models reduce weight over their iron counterparts, though they can still handle the wear and tear that inevitably occurs on job sites,” he said.
Dave Mueller, senior product manager, Klein Tools, said: “Although bending techniques have remained essentially the same for several years, there is a constant goal to improve angle accuracy and consistency over the life of a bender. Over time, the materials used in benders—iron or aluminum—will wear with heavy use. A result of this wear can be distortion of the front hook end that grabs the conduit. This distortion can cause inaccurate results.
[SB]“For ease of use, special markings/targets on the bender head have been added for frequently used bends such as specific degrees of offset, back-to-back bends and center of bend. Also, quick reference charts on the handle labels provide the needed measurements for a variety of offset angles and lengths, saving time on the job.
“Outer-diameter differences between EMT and IMC require the use of a bender head one size up for IMC [thicker wall]. Also, due to the wall- thickness difference, thinner EMT can be adjusted after the bend for minor corrections. The thicker IMC cannot be adjusted. Thus, this requires accurate bending the first time.”
Ken MacLachlan, president/founder/electrician, Rack-A-Tiers, said: “We looked at workflow and the challenge of having to make a number of multiple bends in a row quickly and efficiently while maintaining a consistency of shape.
“Our answer is a bender with a ‘stop’ attached to the bender head to create exact and repeatable bends every time; simplified multipliers engraved into the bender for placing the stop, prior to making offsets and four-point saddles; special 22.5- and 45-degree marks engraved into the bender for placement of conduit bend marks; as well as standard degree marks for stop placement, used together for bending three-point saddles without reversing the conduit in the shoe. Handy reference charts for locating bend marks are attached to the handle.”
Other manufacturers serving the electrical market that supply conduit benders include Ideal Industries (www.idealindustries.com), with aluminum and ductile iron benders for ½- and ¾-inch EMT conduit and ductile iron benders for 1-inch and 1¾-inch EMT conduit; Gardner Bender (www.gardnerbender.com), with ½- and ¾-inch aluminum head benders and iron head hand benders for 1¼-inch iron EMT conduit; and Southwire Tools & Equipment (www.southwiretools.com), which offers three hand bender models: a 1-inch EMT steel head bender; ¾-inch aluminum-head EMT; and ½-inch aluminum head EMT bender.
Mechanical, electric and hydraulic benders and bend carts
Mechanical benders still require human muscle to make bends, but several features improve productivity. Bending shoes are mounted to a two-wheel carriage and are mounted to a convenient working height. Hydraulic benders are for rigid conduit with force provided by manual or electric hydraulic pumps. Electric benders, available in various sizes and models, are for high-production bending. Convenience features include adjustable operating positions, programmable capabilities for making accurate repeat bends at the same angles, remote pendant controls, and the capability to calculate layout measurements for various bends before work begins. Some models can accommodate IMC, rigid and rigid aluminum without changing shoes.
“Productivity is lost when excess time is spent during relocation, setup and planning for making a bend,” Henderson said. “To address the first two issues, electric benders have been improved to limit the time it takes to move and assemble them. Requiring users to lug around multiple shoe groups is a thing of the past, as many benders offer reduced or single-shoe operation. Changeover from one size and type of conduit to the next has become almost seamless.
“For larger and heavier hydraulic benders, transportation and re-assembly can be a huge time waster. Recent improvements have mobilized these larger benders, allowing convenient storage and quick teardown and setup.
“Benders can only bend so quickly. Much of the opportunity for productivity can be achieved by eliminating user error, reducing the need for manual calculations, and simplifying the bending process. Electric benders have become smarter now with the ability to assist users in the planning stages before the bend is performed. Bender enhancements now include conduit size recognition; calculating where to mark conduit; and built-in, springback calculations.
“EMT and IMC require additional supporting rollers for squeezing during bending; otherwise, the quality of the bend can suffer, and wrinkles may form on the inner bend radius. However, IMC differs from EMT in its setup calculations; IMC has different multipliers in calculating bends, including offsets, take-up, springback, etc.,” Henderson said.
The Southwire Bendstation Pro workstation has a dual-bending shoe for ¾- and 1-inch EMT conduit mounted on four casters to move easily around work sites. Work table height is 36 inches with the capability of holding 900 feet of conduit. An extra shelf stores tools and materials.
Gardner Bender markets three benders mounted on two-wheel carts and three electric-powered benders.
Heat is widely used to soften the plastic for bending PVC conduits. There also are cold-bending devices that do not use heat.
“Demand for bending PVC conduit is growing,” Henderson said. “For underground runs, PVC conduit offers a less expensive method for routing cable, and it has a longer lifespan with minimal required maintenance in underground applications.
“Heaters and blankets can be used to evenly heat PVC conduit, making it pliable and able to be bent by hand into the required geometry. To ensure even heating, PVC plugs can be used to close off open ends of the conduit. This is especially critical in colder environments, where airflow through the conduit could cause irregular and inconsistent heating from the inner diameter to the outer diameter,” he said.
PVC Bendit offers a tool that is inserted into PVC Schedule 50 pipe and conduit and applies heat to permit bending.
“Heating from the inside with our product takes about five to seven minutes for the tool to heat up,” said Mike Warner, manager/co-owner, PVC Bendit. “Once hot, approximately another five to seven minutes to heat smaller diameter pipe. For 3- to 4-inch pipe, it can take approximately 15 minutes unattended time to heat.”
MacLachlan said bending PVC is challenging as you must prevent collapse of the pipe while bending. The company’s cold bending spring is inserted into the pipe to support walls during bending.
“The spring bender is simple, portable, and doesn’t require electrical power,” he said. “The user can cold bend rigid PVC pipe without [the] pipe collapsing or fracturing. It is faster and easier than cutting and gluing factory fittings. For smaller sizes, the spring is inserted into the pipe and bent across a knee. Bigger springs are ideal for maintaining pipe integrity when using other bending methods. Ten sizes are available for pipe from ½ inch to 4 inches in diameter.”