COMPACT EXCAVATOR – Beyond Excavation

Excavators are the ultimate digging tools, and compact excavators are supreme when it comes to urban areas and confined jobsite applications. But they just don’t dig. Excavators can take a variety of attachments, ranging from simple buckets to complex drilling tools. Below we discuss four of the most popular attachment options for compact excavators (also called mini excavators).

All Thumbs

Pair a thumb attachment to a compact excavator bucket and you have steel jaws that can capture, clutch and collar objects as diverse as big landscape rocks and as awkward as rebar debris. Thumb attachments are great for picking and placing brush and trees, clearing land and aiding in demolition. They work well with moving concrete during road building and repair, logs in land-clearing applications and debris from demo work.

There are two main types of thumb attachments — mechanical and hydraulic. Hydraulic thumbs can open and close with the help of a hydraulic cylinder. Operators are able to reposition the thumb from inside the machine using controls. A mechanical thumb stays rigid or fixed. Rigid thumbs must be adjusted manually and locked into place. Rigid thumbs use the bucket to pinch materials in order to move them from spot to spot. Thumbs are usually categorized by the weight class of the excavator. Bucket size is also considered. Most thumb attachment manufacturers and installers help to design around different makes and models of excavators.

Pricing ranges from $2,000 to $5,000, with rigid thumbs being less expensive. No minimum requirement flow is necessary as all compact excavators offer more than enough hydraulic power to power a thumb, but some machines may require a pressure relief valve installed in the compact excavator if it does not have one.

Hammer’s Away

Many contractors rely on compact excavators for powerful and precise demolition work. Whether you’re working on sidewalks, curb work, parking lots or demolishing larger concrete structures, projects near roadways or in urban areas often require the small footprint and maneuverability of a mini ex with a hammer. Most lines of breaker attachments are available to accommodate carriers anywhere from 3,000 up to 160,000 lbs (compact excavators typically weigh between 2,000 and 30,000 lbs), so the first thing you’ll need to know in order to choose the right breaker attachment is the weight class of the carrier.

Additional considerations for the carrier itself are tipping load, the length of the stick, overall lift capacities and its hydraulic flow characteristics, such as the operating pressure, hydraulic flow rate and auxiliary flow rate.  The next step is to select the right breaker attachment. No matter what attachment an operator wants to use on a demolition project, the key to productivity is to make sure the machine’s hydraulic flow and weight is matched to the attachment, and that it is easy for operators to change out and operate.

With dust, debris and machine exhaust, proper ventilation of an indoor jobsite is vital. Since indoor demolition may be in an enclosed area, ventilation techniques should be selected based on the job’s location. On top of keeping a steady stream of clean air, a scrubber/catalytic muffler should be installed on the machine. The hydraulic hammers and breakers specifically will range in price from $5,000 to $30,000, depending on the configuration and what size excavator it will be used on.

Grapples of All Sorts

Oftentimes, thumbs paired with buckets don’t offer the appropriate grasp for bigger and more accurate job descriptions. That’s where a grapple or clamshell-styled bucket can come into play. The fixed grapple is the most popular style of grapple for compact excavators (two jaws — one with three tines and one with two tines — making a mechanical hand).  The grapple reacts to the bucket curl, rolling out to open and curling up to grip timber, pipes, boulders, rocks, demolition and debris. This attachment may require that you weld a mount to the dipper arm of your excavator, allowing the operator to use the bucket curl cylinder to close the grapple. Sizes are often determined by the size class of the compact excavator (operating weight), but manufacturers often build fixed grapples with sizes from 24 to 36 in.

Fixed grapples can cost from $2,500 to $5,000 and are easily installed using the compact excavator’s universal quick-attach system. If you’re looking for something a little bigger, more maneuverable and more precise, then rotating grapples and rotating buckets are the ultimate, accurate iron fist on the jobsite. With multi-function capabilities and 360-degree rotation, a rotating grapple attachment allows a compact excavator to do precision landscape work or heavy-duty scrap and recycling applications, twisting the grapple on a rotator for quick and skillful pick ups and deliveries.

A rotating dirt or clamshell bucket can excavate and dispose of dirt, sand or gravel in a very exact manner, and a rotating boulder bucket can grip a myriad of awkward jobsite products and materials for perfect placement on your project. Rotating buckets and grapples are not cheap (they range in cost from $7,000 to $10,000), but for professionals who use them (utility, demolition, timber and landscape contractors), they will use this implement all day long in heavy-duty cycles. There are lots of other specialty grapples on the market: log grapples; unigrabs; felling heads; sorting grapples; demolition grapples; block manipulators; grapple saws; and pipe jaws.

Buckets of Options

The bucket is a seemingly simple attachment that actually has incredible depth and variety — not only in size, but in style and functionality as well. Take a standard bucket for instance. On a 4- to 5-ton rated excavator, a bucket’s width ranges from 12- to 36-in. While the standard width on that class machine is 18 in., a contractor might opt to go with a wider bucket with a larger capacity for jobs such as excavating a basement or pool or digging for drainage. An 18-in. (average size) bucket runs about $1,000, give or take a couple hundred depending on which way you move on the bucket size spectrum.

Besides width, there is the decision whether to invest in a heavy-duty-style bucket. Despite being heavier than a standard bucket, due to being made of steel, which slightly shaves down the excavator’s load capacity, a heavy-duty bucket can perform the same functions as a standard bucket, and it lasts longer. For approximately $200 more, depending on the manufacturer, you get an extra 60 lbs of steel in your bucket for increased durability.

The range of options for standard buckets doesn’t end there; the teeth of the bucket also play an important role in bucket usage. Teeth are generally required for common digging jobs with the exception of frozen ground or solid rock. Specialized teeth such as Tiger or Sharp teeth are designed for rock applications. Using the bucket teeth improperly, as a concrete breaker for example, will lead to teeth damage, among other problems. While crimp-on, top-pin and side-pin teeth make replacement easier, there are some buckets with welded on teeth, which would require a digging dentist to weld on a new tooth.

A specialized bucket helps develop the force and power for a specific job, which takes strain off of the machine. For example, a coral rock bucket can increase digging force by 20 percent, with its shorter tip radius and increased number of smaller teeth that protect the bucket’s edge, when used for peeling actions required for digging coral rock.

Similarly, a cemetery bucket is perfect for carving the flat, level walls of a grave, but its small capacity would make larger digging projects long and tedious. Ditching and tilting buckets are great for cleaning and forming ditches, but their smooth and flat front edge just won’t do when the job calls for pavement removal — that would warrant a pavement removal bucket designed for prying.

When it does come time to replace that trusty bucket, the price range varies between $500 and $3,000, depending on the size of bucket and the size and brand of your machine. Specialized buckets tend to be a bit more expensive given their specific designs.

Keith Gribbins and Kelly Pickerel are editors with Compact Equipment, based in Brecksville, Ohio.