Compact backhoe loaders: 9-foot dig depths and under

Compact backhoes are now commonplace in utility markets – most noticeably used by plumbing and electrical contractors. Their size and power is perfect for maneuvering in tight surroundings. Their hydraulic power allows the use of hammers, augers and other attachments, while their ability to dig 9-foot-deep trenches up to 36 inches wide is ideal for water and electrical line installation.

Compact backhoes have other advantages as well. All the models in the 9-foot-dig-depth class (and under) weigh less than 10,000 pounds. Most, in fact, weigh around 6,000 pounds. They are small enough to be pulled on a trailer behind a heavy-duty pickup or small dump. In most cases, the driver doesn’t require a CDL to transport them.

Right now, small contractors are still the primary users of compact backhoes. “But you’re starting to see a mix of larger contractors and larger construction firms using them as well,” observes Tom Sieper, product manager, Kubota. “Contractors who have traditionally used larger pieces of iron are being attracted to compact backhoes for their size, performance and also because of the significantly lower up front investment needed to buy them.”

“These machines are about replacing hand labor,” says Robert Cunningham, president, Terramite. “They’re easy to operate compared to skid-steer loaders. A skid steer has a short wheelbase and fixed axles. A compact backhoe’s long wheelbase and oscillating front axles give it a smooth ride and help it cover tough terrain. All of these traits are perfect for small contractors who don’t have large pools of labor available to do clean-up and light digging work.”

Fill the hole in your fleet when spec’ing compact backhoes
As with any piece of equipment, application is your first concern in the spec’ing process. Typical dig depths, front loader and backhoe bucket dimensions and capacities will go a long way toward determining which make and model of compact backhoe is best suited for you.

“Size the machine to fill the ‘hole’ in your fleet,” advises Glenn Wright, product manager, John Deere Worldwide Commercial and Consumer Equipment Division. “To do this, review all the applications required in your construction business, then match them against the available units in your equipment fleet. Look for equipment that might be oversized or less efficient at completing each particular task, or equipment that might not be available at the time the task needs to be performed.”

Once you’ve determined where any holes in your fleet are you can begin considering specific compact backhoe models for your applications. Wright says during this phase of the specification process you need to size potential machines for their intended primary task. “This is where dig depths, bucket capacities and lift capacities become important,” he says.

Another way to ensure productivity is to size the machine for the time available to complete the task. “Larger machines generally complete similar tasks quicker than smaller machines,” Wright notes. “All machines have limitations, particularly in construction applications. Look at how you’re sequencing your jobs. You need to perform tasks quickly so subsequent construction steps can be undertaken to complete jobs on time. Make sure any compact backhoe being considered for your fleet has the horsepower, hydraulic power and flexibility required for your time constraints.”

Wright says you also need to consider a prospective machine’s weight and its overall balance as well. When assessing a machine, he suggests extending the backhoe in a tripod-digging stance to determine how much weight is on the front of the machine. “This will help you avoid having an unstable machine in digging and lifting applications,” he says, “and help ensure that it will perform to your satisfaction in rough or uneven terrain.”

Optimize buckets for effective trenching work
“You’re not going to have the dipper and stick options typically found on larger backhoes,” says George Chaney, product marketing manager, compact products, JCB. “On larger machines you can spec different options, increasing your dig depths from 14 to 17 feet. You can also spec extendible dippers that increase dig depths to 21 feet. But the required dig depths for compact backhoes are pretty well set.”

“Options like extendible dippers are expensive and heavy, which defeats the advantages of using a compact backhoe in the first place,” Sieper adds. “If you’re regularly digging trenches more than 9 feet deep, you need to spec a larger machine. But if 9 feet is sufficient, and you’re having trouble moving your large backhoes around on your jobsites, a compact machine is definitely worth taking a look at.”

“Remember that you can configure the teeth and the cutting edge of your backhoe bucket to maximize productivity,” Sieper says. “You can spec more aggressive teeth like Hensley’s Tiger Tooth for tough soils, or a spade tooth design for lighter digging conditions. Just be sure to match the ground engaging tool to the application or job at-hand to maximize performance.”

Boom strength, weight and shape can all impact productivity
Most compact backhoe loaders use straight boom configuration. But several companies, notably Terramite, recently introduced excavator-style curved boom on their compact backhoe models. “A curved boom increases productivity by maximizing digging depth with a minimum of trench cut,” Cunningham says. “This is an important consideration for most compact backhoe users, since they are often required to restore an excavation site to its original condition when the job is done. Curved boom structures also provide better truck loading ability, making it easier to clear side-boards and position materials in the center of the truck bed.”

Regardless of the type of boom you select, be sure to check the overall weight of the boom and dipperstick structures. They are the largest moving components on the machine during digging operations and a productive balance here is as important as it is for the backhoe as a whole. The boom and dipperstick should be heavy enough to provide durability under the force loads created when digging. They should not be too heavy, as each time the motion of the boom is stopped, the inertia of the movement must be stopped, burning extra fuel and decreasing cycle times.

“Also, look at how the hydraulic cylinders are arranged on the boom structures,” Wright says. “Their layout is a good indication of where stress loads will be placed on the boom structure.” A good way to do this is to lay the backhoe structure out flat (extend it fully), and then follow the lines of the cylinders from the bucket to the swing frame. According to Wright, the ideal cylinder layout should not intrude into any portion of the boom structure. “This way,” he says, “all of the load forces placed on the boom will be kept to a minimum, increasing its overall life and productivity.”

Backhoe options can increase productivity
As compact backhoes continue to evolve, they are adopting bigger machine features like servo hydraulic controls and side-shifting backhoes. According to Chaney, both features can enhance productivity for you in many compact backhoe applications. “Servo controls give you smooth control throughout the backhoe’s range of motion and allow precise boom movements,” he says. “There’s no fighting a jerky, uneven boom with servo controls, which let you work faster since there are no wasted boom movements.”

Kubota, JCB and Bobcat have also introduced side-shift backhoes on machines in the 9-foot-dig-depth class in order to maximize operator productivity. “There are many advantages to a side-shift backhoe in digging applications,” Chaney says. “If you’re digging a straight trench up against a foundation (or other type of obstacle) with a center-mount machine, you’re going to have to park the backhoe at an angle and then angle your boom off 90 degrees to dig that trench. And you’re constantly going to have to reposition the machine as you move down the trenchline.”

But, notes Paul Anderson, loader backhoe product manager, Bobcat, a sideshift machine has the ability to pull up parallel with an obstacle and then slide the boom over right next to the rear tire, which is parked parallel to the structure. “This lets you dig a straight trench all the way along a wall, foundation or any structure,” he says. “And you only have to pull the machine forward when you need to advance the trench.”

“The sideshift backhoe has been slow to develop on bigger backhoes in the U.S. market,” Anderson adds. “But the increased use of mini excavators has demonstrated the value of digging up next to buildings, curbs and other obstructions. The sideshift design offers advantages for the compact loader backhoe when using it as a front loader or with other front-mounted attachments. The sideshift allows the backhoe to be tucked up nicely behind the machine for improved maneuverability and lessens concern for hitting something with the hoe.”

If you’re planning on using backhoe attachments, Kubota’s Sieper says it’s a good idea to spec your compact loader with a backhoe removal system. “These systems allow you to easily take the backhoe off of the machine entirely,” he says. “Once it’s out of the way, a three-point PTO hitch is exposed, giving you the option of running attachments with mechanical or hydraulic power. You can put a post hole digger on there, brush cutters, trenchers or other attachments and not have to worry about getting a separate piece of equipment for the job.”

Focus on lift capacity for load-and-carry performance
Many contractors look at loader bucket capacity as one of the key specifications for a productive backhoe loader. While this is a good approach for larger machines, Wright says you’re better off looking at lift capacity on smaller backhoes. “Lift capacity needs to be considered carefully and in conjunction with a machine’s overall weight and balance,” he says. “There are a lot of machines out there that can lift capacities of more than two-thirds their total machine weight. But remember that if your bucket isn’t sized accordingly, and if the machine isn’t configured with a substantial counterbalance, you’re going to have an unstable, unsafe machine on your hands.”

Loader bucket widths, as well as bucket carrying capacities, also need to be closely matched with the machine. Most contractors prefer front buckets that are slightly wider than the machine’s tread width to facilitate digging or back dragging. To meet this demand, most compact backhoe loader buckets available today run from 62 inches to 72 inches wide. Depending on the width of the machine, these buckets generally overlap the front tires by about 2 1/2 inches on each side of the unit.

“You need to try and spec as big a bucket as you possibly can to increase overall productivity,” Chaney says. “You also need to pay attention to your required dump heights and the dimensions of the dump bodies you’re using, or any other obstacle you know the machine will have to clear.”

The key to front bucket selection, says Sieper, is to not overload your machine. “Remember that too big a bucket can degrade productivity as badly – or worse – than a bucket that’s too small,” he says. “Plus, you’ll be overstressing your machine and shortening its lifespan.”

But once you’ve settled on bucket width and capacity, Sieper says you still need to decide if you want to go with a heavy-duty bucket, or if you can get by with a standard one. “Both have advantages and disadvantages,” he says. “The heavy-duty bucket is going to stand up to abuse much better than a standard bucket, and you’ll worry less about damage and repairs with it on your machine. But if you’re not digging in hard rock or other abrasive materials, a standard bucket might be the way to go. It will cost less up front, and it will weigh less, allowing you more bucket capacity in load-and-carry work.”

Multi-purpose combo buckets – four-in-one buckets, which hydraulically open and close – are another option. “A four-in-one bucket can increase your machine’s dexterity in a number of ways,” Chaney says. “You can use the bucket’s backside as a dozer blade for light grading work, and you can meter the spillage of material out of the bucket for precise placement when dumping. You can also skim with the front side of the bucket by opening it and tilting it forward and delicately shaving material off.”

“Using the SAE standard attachment coupler for skid-steer loaders on the compact loader backhoes increases the already broad range of attachments you can choose from,” Anderson says. “With auxiliary hydraulics, loader attachments like augers, breakers, grapples, angle brooms, snow blowers, angle blades, tillers and even trenchers can be used on the unit without having to remove the backhoe.”

Theoretical horsepower an effective measure of hydraulic performance
Hydraulic capability is an important specification regardless of machine type. Compact backhoes deliver in this department as well, with their ability to handle a wide range of attachments. “Most backhoes in this size class have hydraulic flow rates ranging from 6 to 10 gpm,” Cunningham says. “Sometimes contractors want to use larger attachments. But you need to remember that even if the backhoe can physically handle the attachment, if the flow rates don’t match, you’re not getting top production from it. Carefully matching attachments is an easy way to get the most productivity from your small backhoe.”

Wright suggests looking at theoretical hydraulic horsepower output when you’re considering a machine. You can calculate theoretical hydraulic horsepower using a simple engineering formula: multiply the unit’s hydraulic flow rate (gpm) times its hydraulic pressure (psi). Then divide this total by 1,714 for the machine’s theoretical horsepower output.

“The higher the theoretical horsepower figure, the quicker and easier it will be to get a difficult job completed,” Wright explains. “Hydraulic horsepower is taken for granted on larger machines because of their larger engines, higher volume pumps and higher system pressures. When you get into smaller machines, hydraulic horsepower is not necessarily guaranteed, due to the diversity in engine sizes, hydraulic pump configurations and system operating pressures. Because most tasks will be performed using hydraulic cylinders operating boom structures, however, it is critical to productive machine performance.”