Compact trenchers have been a flagship machine in the underground industry since Ed Malzahn engineered the DWP Service Line trencher in 1949. In the 70 years since, trenchers have developed into some of the most efficient machines in the market and can be used in a variety of applications. Ride-on machines, in particular, are an efficient option for underground professionals facing more extensive trenching projects like those deeper than 2 ft and/or longer than 20 ft.
While less invasive trenchless options like horizontal directional drilling (HDD) are attractive to many contractors, ride-on trenchers are still the quickest, simplest and most affordable solution if there are no issues with creating a trench. There are no certifications required to rent and use a trencher (though we do recommend that operators make use of a certified training option to ensure they understand machine best practices), and there are fewer machines required on-site than with an HDD project.
One of the top reasons ride-on trenchers continue to be a valuable asset to underground construction crews is the variety of attachments that offer the ability to meet different construction needs with one machine. From the standard trencher attachment to a more specialized microtrencher, here are some of the attachments that can improve the ROI of any ride-on trencher.
The standard trencher attachment is the bread and butter of any ride-on trencher machine. It generally comes pre-installed on a ride-on trencher. The standard trencher attachment will dig approximately 4 to 5 ft into the ground and create a trench 6 to 12 in. wide, although different manufacturers will offer varying size options. With standard trencher attachments, contractors can efficiently create trenches to install irrigation lines, fiber or cable. The most popular trencher attachments will come equipped with a combination chain that is fitted with both shark tooth and cup tooth chains to cut through a variety of soil conditions.
When using a standard trencher attachment, it’s important to always let the trencher work at its own pace. Forcing a trencher to cut faster can lead to broken chains and downtime for repairs. It’s also advised to inspect the chain at the start of every job to ensure that the chain has the proper tension. A good rule of thumb for determining this is to follow the two-finger rule — when inspecting chain tension, two fingers should fit between the chain and the lowest part of the boom when the boom is parallel to the ground.
Contractors should also check to ensure there are no broken teeth on the trencher attachment. Both poor chain tension and broken teeth can reduce its effectiveness.
A rapidly growing technology in the trenching world is microtrenching. Most commonly used for fiber installation, microtrenching attachments allow for a narrower trench to be created than with a standard trenching attachment. For instance, a microtrencher will cut a trench 1/2 to 3 in. wide. This narrower trench saves contractors backfilling time and cost since less backfill will be needed.
Microtrenching is typically done in the gutter pan that parallels the road where the asphalt meets the concrete of the curb. By cutting a narrower trench when cross cutting and trenching on the side of the road, contractors don’t need to stop traffic, saving on traffic redirection headaches and associated costs. There are two typical blades that most microtrenching attachments will use. The first is a conical style bit that rotates in a holder and functions like a traditional rock saw. The second is a PDC blade which is composed of diamond with carbide. The conical bits are generally the more affordable option between the two, but diamond PDC blades are growing in popularity due to their cleaner cut and longer lifespan. While a conical bit will be effective through around 4,000 ft — meaning that contractors will likely need to replace bits daily — a diamond PDC blade will last around 20,000 ft before it needs to be replaced.
Unlike most other ride-on trencher attachments, a trencher-backhoe attachment is most often stationed at the front of a machine so that it can operate in conjunction with another attachment. The primary function of a backhoe attachment is to start and finish a trench, similar to an entry pit and an exit pit in HDD. A backhoe attachment is beneficial, especially on jobsites in which the start and end of a trench are in close proximity to urban hazards like fencing or existing landscape structures. A backhoe attachment is also used in rehabilitation and repair projects because it allows for more precise digging than a standard trencher attachment. The typical backhoe attachment starts with a 6-ft digging depth and has a bucket width of 12 in. As machine size increases, so does the backhoe size.
A saw attachment — also known as a rock saw — is a circular blade that is similar in appearance to a microtrencher. This attachment is used to cut through difficult and rocky terrain. The most common saw attachments will dig down to a depth of 16 to 48 in. and typically use a conical bit blade with carbide. As a result, it’s important to consistently check the blade for wear. As saws are constantly used in rocky conditions, their bits will wear down faster than standard trencher teeth.
A plow attachment is most commonly used to bury flexible pipe, conduit and cable. The plow is an attractive option in these applications as it offers the ability to install the application as the machine drives. Plows also create less ground disturbance than a standard trencher because they do not create an open trench. However, plows may be difficult to operate in hard or rocky ground conditions. There are two different styles of plow blades: a pull blade and a feed blade. A pull blade does what its name implies and will pull a cable, conduit or fiber behind the blade to install it underground. A feed blade will have a feeding chute on the attachment to allow conduit to be fed down through the attachment and into the ground.
It’s important to remember that anytime crews are digging into the ground, they should always call 811 to get a jobsite located. Understanding where existing utilities are located is one of the most important steps in mitigating damage and reducing the chance of costly strikes. Additionally, it’s important to take precautions when installing attachments. While attachments are built to have the ability to be changed out, we always recommended that users contact a local equipment dealer when looking to remove or install attachments. Personnel at a dealership have been trained and have access to the proper equipment to ensure a safe attachment exchange.
Ride-on trenchers have long been one of the most efficient pieces of equipment for any underground construction project. But with the growing ability to customize machines with attachments to meet almost any jobsite need, their benefit is growing too.
5 Tips for Choosing a Trencher Attachment for a Skid Steer or Track Loader
1. Depth and Width
Determining the depth and width of the trench required is the first step in sizing a trencher attachment. Most manufacturers offer chain widths from approximately 6 to 14 in.
2. Ground Conditions
Matching the right trencher to the ground conditions in question is essential too, preventing technical problems and guaranteeing maximum productivity.
Ground conditions help determine the type of teeth best suited to your application. Multiple options in teeth range from tungsten for tougher conditions and earth teeth for softer ground.
4. Host Machine
It is fundamental to match the auxiliary hydraulic flow and pressure of the skid steer or track loader to the trencher attachment.
The trencher motor needs to be configured correctly, balancing the speed and the torque. If too much speed is allowed, the chain will flail. Too much torque, the chain will not move quickly enough.