Wear and tear: cost is not the only factor to consider when buying auto shredder wear parts

Recycling Today, April, 2004 by Deanne Toto

"Time is money." This is a familiar adage to processors of scrap metals, and it is particularly true when the market is sizzling as it is now. When the market is this hot, scrap processors cannot afford to have a shredder down for an extended period of time awaiting replacement hammers or other critical wear parts. Wear part reliability and availability become imperative as the market for scrap metals improves.

Wear parts are essential to a shredder's proper functioning, and operators have to consider more than cost when shopping for replacement wear parts.

Wear parts enable a shredder to run at its maximum processing capability, Art Borin, president of Amsco Wear Products Inc., Goshen, N.Y., says. "Wear parts should not just be designed to control cost, they should he designed to give you the best possible combination of wear life, feed rate, processing capability and, therefore, profitability."

EYEING THE BOTTOM LINE. Greg Stegmaier, product manager for Columbia Steel Casting Co. Inc., Portland, Ore., also stresses the importance of considering more than just the cost of wear parts.

"Do not over emphasize the price of the part," he says. "It's the value obtained by using the wear part that should be the focus of your attention."

Determining the value of a wear part takes observation and calculation.

As you process more tons, as you are able to find the magic combination in your shredder that allows you to process material at a high feed rate, obviously, your costs are going to go down because your produced tons are going to go up," Borin says. "You want to find the happy medium between cost, quality and the ability to process the material in an efficient manner."

Borin says shredder operators should strive to obtain "full-box" shredding, a concept he learned from Jim Mosebach of Metal Management, to maximize the longevity of their wear parts. "You have a burden or a load inside the machine that is not only working on the wear parts, but is also working on other pieces of scrap," he says. Such full-box shredding reduces the wear" on the hammers and other parts inside the shredder box, prolonging their usefulness.

Industry estimates put the average cost of wear parts from $2 to $2.65 per ton of metal shredded. Although John Martinek, vice president of Levand Steel & Supply Corp., Birmingham, Ala., says wear parts for smaller machines could cost as ranch as $5 per ton of material shredded.

"The size of the shredder will make a significant difference in the cost percentage of" replacement parts," Martinek says. Because wear parts have to be replaced more often in smaller auto shredders, they cost more per ton compared to wear parts for larger shredders, he says.

"The cost of wear parts is directly related to how much they shred," Rusty Manning, sales manager for Riverside Engineering, says. "Approximately two pounds of wear parts are consumed for every ton of steel shredded."

It is more difficult to determine the overall cost of wear parts as a percentage of an operation's cost. This number varies by operation and depends on what figures the operator factors into the equation.

Randy Brace, vice president of engineering for Riverside Engineering, San Antonio, says shredder operators' direct shredding costs can be broken down into five categories: labor, wear parts, utilities, maintenance and fuel. He adds that shredders have evolved during the years to shred at higher densities while consuming less energy and fewer wear parts and requiring less maintenance.

"All of these improvements have led to lower costs per ton," Brace says. "On average, the overall percentage of the wear parts to the total direct shredding costs should be between 20 percent and 25 percent."

Brace says that when costs such as waste disposal, depreciation, interest, property and equipment costs and other administrative and overhead costs are factored into the equation, wear parts represent from 5 percent to 15 percent of a shredding operation's total costs.

VARYING DEGREES OF WEAR. Shredder boxes are comprised of a variety of wear parts, including hammers, anvils, rotor caps, end disk caps, pin protectors, side liners, grates and reject doors. While everything within the shredder box receives material impacts and will eventually need to be replaced, the degree of wear varies for each part.

"The expected life on a hammer is a lot shorter than everything else in the mill," Kevin Tort of Riverside Engineering says. Tort is a sales account manager located in Riverside's Moline, Ill., office.

"Hammer cost will make up about 50 percent of total overall replacement casting costs," Martinek says.

Brace says that apart from hammers, castings showing the highest wear rates and replacement costs are bottom grates, anvils/cutter bars, rotor caps, pin protectors and upper anvils/upper breaker bars.

Tort adds that side liners historically have the longest wear. "Depending on what they shred and how much they shred, some customers will have side liners that last a year; some will have side liners that last three to four years."