In spite of the wide variety of materials they handle, all well equipped scrap metal recyclers have at least one thing in common – a good alligator shear. Alligator shears play an important role for metal recyclers by cutting things down to size – literally – enabling shredders to handle oversized materials that would otherwise be difficult or sometimes impossible to digest. They also allow the recycler to “clean” or prepare scrap for shredding by removing unwanted fittings or other parts the shredder may not accept. This adds value to the scrap and improves the quality of the finished frag.

This month, we’ll look at stationary alligator-style shears and provide some basic guidelines for choosing the right alligator shear for your needs.

Feeding the beast

Alligator shears take their name from the style of jaw. The top blade is hinged on one end and is driven by a hydraulic cylinder. Like the swamp dwelling reptile, it exerts tremendous force on the downward stroke, shearing off nearly anything a scrap metal recycler may feed it. But, there are limitations for everything, as we’ll discuss later.

The first consideration a scrap metal recycler should look at is the range of materials he plans to cut. This is known as the “appetite” of the shear. The jaw size and cutting force determines the appetite of the shear. Curt Spivey, vice president of sales and marketing for Sweed Recycling Machinery, Inc., distributors of Ramjet alligator-style shears points out, “Recyclers should know exactly what they plan to process. Most manufacturers publish an appetite guide to help recyclers size the correct shear for their operation. Typical materials include such scrap items as pipe, angle, cable, tubing, rounds, rebar and some I-beam,” he said.

In addition to cutting some items to a manageable length, a lot of times scrap yards must remove certain fittings or clean things off the material they process because they can’t be recycled for some reason. Preparing materials like those for a shredder can bring as much as $20-$30 more per ton for the recycler,” he added.

Don’t stand too close

Alligator shears pack a lot of cutting power, but the force exerted on the material being cut varies widely, depending on the make, model and target application. On the small end, an 8” alligator shear has a cutting force of roughly 25 tons. This is adequate for small diameter rounds, angle iron, rebar and some light gauge sheet. Larger alligators produce as much as 200 tons or more of shearing force – suitable for small I-beams, some plate steel and other heavy scrap.

With that much force being applied, safety is the primary consideration among manufacturers of alligator shears. “Our products are equipped with breaks, guards and blocks to be sure the piece stays secure while it’s in the shear,” said Curt Spivey. According to Sweed Recycling Equipment, a serrated knife-edge, most commonly the bottom-shearing blade, is often used to keep material from moving away from the pivot point while the top jaw is closing under pressure.

Some models offer other safety features such as dual switch controls – a system of two switches placed a few feet apart that require the operator to press both simultaneously to cycle the shear. Standards for machine guards such as those fitted to alligator shears are listed in OSHA regulation 29 CFR 1910.212.

In spite of the huge cutting forces applied, there are some materials better left to the torch or some other means for cleaning or reduction. “Alligator-style shears are great for their intended use, but there are certain things that shouldn’t be attempted,” said Curt Spivey. “Hardened materials such as axles, rail or leaf springs can damage the cutting knives,” he added.

Caring for your alligator

Generally speaking, maintenance on alligator shears is very low. Due to the wide variety of materials processed and the amount of use each shear may get, blades will wear at wildly differing rates. A recycler cleaning larger volumes of scrap or has customers with more cut-to-length requirements will need to inspect his blades frequently to ensure maximum throughput and performance.

When they need attention, most manufacturers recommend that blades, or cutting knives, be replaced rather than sharpened. This is due primarily to the somewhat limited capabilities among most metals recyclers to properly recondition worn blades and restore them to the manufacturers’ original equipment specifications. By replacing blades when necessary, operators can be assured of maintaining the highest levels of safety, performance and productivity.

Bobby Alexander, president of Ft. Worth, Texas-based Strip Technology, Inc., distributors of the popular McIntyre shears said, “Keep it greased. There’s several pivot points on an alligator shear that require lubrication, and the best way to handle that chore is on a regular basis. It’s a lot better to schedule a maintenance routine, say once a month, and be sure it’s done faithfully regardless of how much use a shear may get in between. The habit of performing regular maintenance doesn’t take much time and it’s a lot less costly than repairs,” he said.

Generally speaking, the hydraulic system on an alligator shear requires nearly no maintenance at all. “All the manufacturers use good components to begin with,” said Bobby Alexander. “And they’re well engineered. The hydraulics feature in-line filters for the fluid, pick-up screens in the reservoir and temperature gauges to be sure things don’t overheat. Alligator shears are a bit like 35mm cameras today,” he said. “It’s just about impossible to buy a bad one.”