Bendit has tried different tooth and chain configurations on the machines for winter trenching, including rock chains with carbide bullet teeth, shark teeth and other combinations. This year, he plans to carefully track production in order to come up with the best combination for his company.
"Some people will use a combination chain, which still has the dirt cups on it with the carbide teeth. They alternate them back and forth with varying patterns," Bendit notes. "If you still have some cup teeth on there, it will help clean the trench out a lot better when you're trenching. When you get into a rock chain with only the carbide teeth, it does not clean your trench out very well."
In addition to tooth and chain changes, some contractors will change the boom to a larger-tail roller (LTR). "That larger roller at the end of the boom gives you more surface area for the chain to ride on as it makes the transition around the end of the boom, leaving less chance for the chain to jump off in adverse conditions," Bolay says. These booms also have side plates that enclose the area between the top and bottom of the digging chain, eliminating an opening for debris to get in and cause interference with the chain.
Working in cold temperatures requires special maintenance attention. For example, use oil, fuel and antifreeze that are optimal for cold conditions. It's also a good practice to grease the back end of the trencher at least twice a day.
If you're regularly working in cold climates, it's also a good idea to take advantage of the cold start options trencher manufacturers offer, including a cold-oil bypass, ether assist and block heaters. Also remember that it takes longer for your machine to warm up in the cold.
Infrasource Underground Construction Services, Central Division, Princeton, MN, takes several steps to ensure its trenchers continue to work effectively in the cold Minnesota winters. "The machines all have block heaters on them so we can plug them in at night and in the morning they'll start up," says John Elifrits, operations manager. "We run the same oil as we do in the summertime. But in the winter, we have winter blend diesel fuel up here, which runs anywhere from a 70/30 mix (70% No. 2 diesel and 30% No. 1 diesel) to a 60/40 mix. It thins the fuel out so it won't gel. And we'll also put anti-gelling additives into the fuel when it's really cold."
Chain and tooth inspections are also very important. On a daily basis, make sure the chain is free from debris and that it has the correct tension. This will help you avoid unnecessary chain wear.
"Chain tensioning on the boom is extremely important because the work is so severe that it's putting high tensile and shock loads on the chains. Chains are designed to stretch a little bit, especially in the beginning of their lives," Chancellor points out. "The tensioning is critical to get full life out of a chain. The OEM has specs on how tight the chain should be for that specific boom."
In his area in Indiana, Bendit advises that a mechanic or qualified person examine the chain for wear on a weekly basis. "Daily would be ideal if you have a person on the crew who can recognize these problems before a breakdown," he adds. "We are teaching operators to have a better understanding of preventive maintenance while out trenching."
In the rocky soils of Wisconsin and Minnesota, teeth should be checked at least once a day for wear and damage.
Trench-It, Inc., a Union, IL, utility contractor working throughout northern Illinois and the Chicagoland area, focuses on preventive maintenance to keep its trenchers working in the winter. Road mechanics perform work when needed, but the company really relies on its crews to keep their eyes on the machines.
"Each morning, the crew inspects the trencher — they inspect the fuel and oil, grease it, and tighten and inspect the chain," says Matt Turk, vice president of operations at Trench-It. He adds that crews sometimes perform tooth and chain inspections at noon because of the possibility for wear and breakage in the winter.
Higher trenching costs
On average, contractors reported that the price of a winter trenching job can run anywhere from 20% to 40% higher than a comparable-sized job in the summer. This extra cost can be attributed to several factors.