Properly Picking and Operating Trencher Attachments for Skid Steers and Track Loaders
A small loader with a trencher attachment is perfect for precision cuts. Dig trenches for utility and irrigation systems or power and water lines. Trench close to buildings, walls and fences, and do it with a machine you already have in your fleet — a skid steer or compact track loader.
“Trencher attachments offer significant advantages to using an excavator or backhoe to trench,” says Lionel Smitka, marketing manager with Digga (a global brand of attachments for a variety of compact tool carriers). “In the right hands, it’s faster. Operators can dig a super narrow trench that’s only 4 in. wide, reducing ground disturbance and the amount of dirt needed to be moved. And, the spoils are much finer, making it easier to return into the trench and reducing the amount of settlement due to the reduced amount of air pockets in the fill.”
Trencher attachments for skid steers and compact track loaders offer numerous advantages and opportunities — speed, cost, footprint, comfortable and safe operation from a cab and ultimately more work and revenue out of your host machine. Whether you’re laying cables, trenching drainage systems or installing landscaping, understanding all aspects of what is required when buying and operating a trencher implement will be key to success and satisfaction. Luckily, many manufacturers make trenching attachments that can be customized to suit a wide selection of application needs.
“Trenchers come in a variety of sizes and configurations to ensure they can be used in a variety of ground conditions,” explains Joe Walker, VP of sales at Solesbee’s and Auger Torque USA, which offer six different trencher attachment models with multiple chain and teeth configurations. “At Auger Torque, we could size up and use tungsten teeth chain if the ground is particularly tough, or we could use a trencher for a lower flow machine with earth teeth if it’s light soil. It’s important that the operator understands any limitations they might face when trenching through certain ground conditions and how that might affect the efficiency of trenching.”
Including ground conditions, there are many variables to consider when purchasing, renting or operating a trencher attachment for a skid steer or compact track loader. Make no mistake — these are complex attachments that require safe operation — so let’s start with…
Depth and Width
Determining the depth and width of the trench required is the first step in sizing the correct trencher attachment. Trencher attachments for skid steer and track loaders can be configured to dig depths up to 60 in., using booms 2 to 5 ft. This range allows for plenty of product installs.
“Cat trencher attachments are designed for cutting narrow straight trenches in soil prior to laying electrical, utility, irrigation, drainage, water and gas lines,” says Matt Walsh, product and application specialist with work tool attachments at Caterpillar Inc. “Machine-mounted trenchers are ideal for residential, commercial, agricultural, building construction, lawncare and golf course maintenance applications.”
Most manufacturers supply trenching attachments with chain widths from approximately 4 to 14 in., allowing you to dig various depths. “Typically a 4-ft boom with a 6-in. wide chain is the most popular,” says Jim Hunt, sales and marketing manager with Premier Attachments, which makes five different models of trenchers for mini-skids, full-sized skid steers and mini excavators. Typically, as the chain width increases, the allowable dig depth decreases. This is a good point to remind readers that we’re discussing trenching attachments here — not dedicated walk-behind trenchers. For trenching a significant depth and width, or if your job is to solely dig trenches, then a designated pedestrian or even ride-on trenching machine may be a better fit.
Proper Chain Tension
Matt Walsh, Product and Application Specialist, Work Tool Attachments, Caterpillar
Proper chain tension is critical to achieving maximum performance out of your trencher. We recommend adjusting tension according to the operating manual. The rule of thumb is that the chain should hang away from the underside of the boom by 1.5 to 2 in. This proper chain tension will allow some spoil to pass through the chain and sprocket interface, reducing the likelihood of stalls/jams. For this reason, it’s better to keep the chain too loose rather than too tight. A chain that is too tight will put added wear on other parts of the machine, robs the trencher of horsepower and productivity and can prematurely wear out the chain. Conversely, chain tension that is too loose can cause a chain to walk off the end of the idler or jump the sprocket. Inspect and replace worn or broken teeth. Using dull teeth can cause the chain to excessively stretch causing premature wear. Worn teeth reduce digging efficiency and increase shock loads to other trencher components. In wider cut/chain configurations, outside teeth do most of the cutting and typically wear first. Besides the chain and teeth, the front idler and idler bearings are probably the next most common wear point on a trencher. Lubrication of the front idler is recommended every 10 hours of operation. The rest of the grease points (all identified in your maintenance manual) should be hit daily.
Ground Conditions and Teeth
Matching the right trencher chain and teeth to the ground conditions in question is essential to keeping costs down, preventing technical problems and guaranteeing maximum productivity and efficiency when moving through the ground. Using a machine too small for the workload will limit production and cause unnecessary wear on the attachment. A trencher attachment too large for a job will not be able to operate effectively. Also, using the wrong teeth could slow production, waste fuel and wear or even harm both machine and attachment. Understanding the type of the earth you’re trenching into will be important.
“Skid steer and compact track loader trencher attachments can easily dig in light to moderately compacted, sandy, loam soils and loosely packed gravel,” says Gustav Krejcha, product marketing manager, construction equipment attachments, for Case Construction Equipment Parts and Service. “But solid rock is not suitable for skid steer or compact track loader trencher attachments.”
Ground conditions help determine the type of teeth and chain combo best suited for the application. Chains should be available in a number of different teeth configurations for trenching in soft ground, mixed ground and even permafrost. Manufacturers often use different names to describe certain teeth. Usually, tungsten or carbide teeth are geared for tougher ground conditions and earth or standard teeth for softer ground. Other fun trencher teeth names might include cup, bullet, shark, fin, terminator, scorpion and rock and frost. Ask the dealer to explain each tooth type. Some attachment makers offer the added feature of interspersing various teeth in useful combinations — like using earth teeth with cup- or paddle-shaped teeth — which helps to remove spoil from the trench, giving the clean finish customer’s want.
“The Case trencher chain offering is extensive from tooth every station [TES] to tooth every other station [TEOS] with rock, frost and shark tooth chains in 6-, 8-, 10- and 12-in. wide chain sizes,” explains Krejcha, breaking down the Case trencher chain line into five major combinations.
Tooth Every Station (TES): Designed for standard digging conditions in light to moderately compacted sandy, loam soils and loosely packed gravelly soils. These are identified as typically good digging conditions.
Tooth Every Other Station (TEOS): Designed to be the most productive in wet, sticky ground conditions, such as wet clay, gumbo, etc. TEOS allow sticky soils to be discharged as it comes around the head shaft sprocket allowing the auger to pick it up and discharge soil to the side of the trench.
Rock and Frost Chain 50/50 (50 percent rock and frost teeth and 50 percent cup teeth): Gives the highest production in frozen, highly compacted or rocky soils. The bullet-shaped rock teeth break apart tougher soil and rock, allowing the cup teeth to pick it up and clean the trench. It is aggressive in tough conditions, but not as productive in normal or light soil conditions.
Shark Tooth Chain 70/30 (70 percent shark teeth and 30 percent cup teeth): The 70/30 chain should be used in compacted soils, light frozen ground, baked hard clay, shale or rocky soils. Shark teeth will slice, break and relieve the tough soils, allowing cup teeth to follow and clean the trench. It is not as productive as the TES chain in normal digging conditions.
Full Shark Tooth Chain (100 percent shark teeth): A full shark tooth chain is recommended for fracturable rock, shale, caliche or conditions with little or no loose soil. It will not efficiently clean the trench in sand, silt and high-moisture clay conditions.
Host Machines
The trencher attachment must be correctly matched to the skid steer or compact track loader to achieve optimum operation and efficiency. It is fundamental to match the auxiliary hydraulic flow/horsepower of the host machine to the trencher attachment. This will result in the most efficient trenching.
When someone’s discussing a skid steer’s or track loader’s auxiliary hydraulic system, they are describing the pressurized hydraulic oil that is being used to power the attachment. The main specs are hydraulic pressure (psi) and flow rate (gpm), and units can come with standard- or high-flow auxiliary hydraulic options. Standard-flow skid steers and track loaders range between 8 and 30 gpm (3,000 to 3,500 psi), while high-flow units range between 30 and 50 gpm (4,000 to 5,000 psi). “Our trencher lines are designed for machines with a flow of 8 to 39 gpm and a psi range of 2,500 to 3,500 psi,” says Hunt.
“Cat’s standard flow and pressure is adequate for a wide variety of trencher applications,” explains Walsh. “Our attachment strategy and strength are matching the attachment to the machine’s performance capabilities.”
Walsh notes high flow allows for two times the torque via the trencher drive shaft and two times the chain pull force compared to Cat’s standard-flow trenchers. This allows operators to attack more severe digging conditions at more aggressive angles.
“High flow can have its advantages depending on the trenching application, duty cycle and machine flow, but it’s not critical for most jobs,” says Smitka. “With a price difference of around $1,300, high-flow models are generally reserved for serious trenching operators.”
Whether standard or high flow, trencher attachments will require continuous hydraulic flow while the host machine moves slowly backwards, so an automation feature like creep control is ideal. “The creep function on our skid steers, track loaders and compact wheel loaders allows the operator to travel in reverse at a slow, steady pace, which is perfect for trenching applications,” says Walsh.
Motors, Crumbers, Options
Most trencher attachment makers offer multiple features and benefits. Some units feature direct motor drives and others feature chain reduction drives. Direct drives often offer more chain speed but lose out in long-term durability and the all-important area of torque. Heavy-duty chain reduction drives offer a dependable and economical method of maximizing digging power at an affordable cost. That motor needs to be configured correctly, balancing both speed and torque. If too much speed is allowed, the chain will flail and spoil will spray around the area. With too much torque, the chain will not move quickly enough, leaving spoil in the bottom of the trench.
“Auger Torque uses only the highest quality hydraulic motors, which allow flow rates up to 39 gpm,” says Walker. “This gets amplified by Auger Torque’s own bullet-proof planetary gearbox, which means that our trenchers have the reliability operators need and the power to ensure your trenching is carried out with ease. Our epicyclic gearbox system allows the motors output torque to be multiplied with extreme efficiency as well as ensuring the durability and reliability operators need.”
When considering precision, using a depth control skid plate and making certain it’s flush with ground will ensure accurate depth. “A precision depth control system ensures consistent trench depth along the entire length,” notes Walker. “We have three depths available on certain Auger Torque models. Once set, the trench depth remains constant, removing the need for manual measuring or additional digging or checking by the operator.”
Most trenchers come standard with a crumber, which helps remove soil from the trench and provides a clean, smooth trench bottom. Certain trenchers can reverse the chain direction. “Our variable speed, bi-directional, gerotor style motor allows the operator to reverse the chain rotation to clear the trencher in the event of a stall,” explains Walsh. There are also side shift options, which provide attachment flexibility when working next to buildings or objects, shifting the trencher left and right without moving the host machine.
“Case has two-position manual side shift mounting with optional infinite positioning using our hydraulic side shift cylinder assembly,” says Krejcha, noting many other options and features are available. “We have boom and crumber assemblies in 30-, 36-, 42-, 46- and 60-in. sizes. The pivoting crumber shoe and bar assist with help soil removal from the trench. A low-profile dirt shield helps improve operator visibility. A built-in skid shoe can provide positive depth control for the auger, and bolt-on replaceable wear strips on the boom extends boom life.”
Compact track loaders are the most popular category of compact equipment in America. Learn why with loads of track loader features right here.
Trencher Attachment Operation
Trencher attachments can range in purchase price from $4,000 to $10,000. After properly pricing and selecting a trencher attachment, make sure operators know how to operate it — and don’t forget to call 811 before digging!
“Trenchers are designed to operate with the loader traveling in reverse and the machine auxiliary hydraulic operating in continuous flow,” explains Walsh. “We recommend operating with the boom angled down between 45 and 65 degrees from the horizontal position for maximum performance in general trenching applications. Trenchers can be operated at steeper angles, up to 90 degrees below grade, for deeper trench requirements or vertical wall work. However, travel speed, cutting efficiency and spoil removal will be negatively affected at steeper cutting angles.”
When trenching, it is important to have the trencher chain properly adjusted (check out our sidebar above). If the chain is too loose or too tight, it will lead to inefficient trenching. “Let the chain do the work,” says Hunt. “Lay the trencher down and ease into the cut, do not drive the nose of the trencher straight into the ground.”
Operators should start the trench ahead of where they need to be at full depth, angle the trencher about 45 degrees and lower the trencher while reversing the loader at a rate not to bottom out the crumber.
“The position of the spoil auger is critical to the trenchers efficiency at getting the job done,” says Smitka. “Too high and it’s not clearing the spoil from the trench properly causing the spoil to fall back in the hole and be brought out again. The operator is essentially removing the same spoil from the trench multiple times reducing progress. If the spoil auger is too low, it digs into the ground slowing the chain speed and robbing the trencher of power and efficiency.”
Learn even more about trencher attachment operation, selection and maintenance at compactequip.com.
Keith Gribbins is the publisher of Compact Equipment.
Trenching Safety
Before commencing trenching work, undertake all safety checks, site surveys, hazard recognition and risk assessments on the site where you’ll be working. Make sure you’re wearing all of the appropriate safety gear like goggles, high-vis, appropriate shoes, gloves, etc. Also, be sure to call 811 before you dig. Follow all safety precautions outlined in the operator’s manuals of the attachment and parent machine. Check the equipment (trencher attachment and parent machine), ensuring that all parts and systems are in good operational working order and not showing any signs of wear. If in doubt, diagnostic equipment and professional advice should always be considered before carrying out any work.
