Q&A: Talking Mini Excavator Attachments with Caterpillar’s Kristin Stout

Cat mini excavator with breaker

Buckets, thumbs and breakers are just a few examples of the basic attachments mini excavator operators must have for everyday work. These tried-and-true tools serve many purposes for a large variety of applications. But what about when a job calls for something a little more unique or specialized? What are some mini excavator attachments operators are using beyond a bucket? Below, Kristin Stout, product application specialist at Caterpillar, discusses both common and unique attachments for mini excavator operations. Let’s see what she had to say…

Stout: As everyone knows, buckets are the most common attachment on a mini hydraulic excavator. Pairing perfectly with the bucket, we recommend using a thumb. This now allows the excavator to grab and move various material rather than just the ability to dig. Cat has a variety of other attachments that increase the versatility of a mini hydraulic excavator (MHE) and some of the most popular attachments include augers, hammers and vibratory compactor plates (CVP).

Augers are used to help customers dig holes for footers, to set posts, plant trees, etc. These can be paired with different bit options based on your soil conditions as well as desired hole diameter and depth. Hammers are for that demolition environment when you are trying to break apart or through material. Cat has two different product lines of hammers for both the utility version for the customer that only needs one on occasion or a premium version with features such as auto shutoff, blank fire protection, for those that tend to have more dedicated needs. Cat has a wide range of different tool types for the hammers, such as moil, cone, chisel, spade, etc. to perform different breaking actions — allowing the material to break down effectively.

Lastly, vibratory compactor plates, or CVPs, are the best attachment for compacting soil, sand, gravel and other materials. They are commonly used prior to laying pipe or pouring concrete. Cat now offers two new sizes, the CVP28 for the 5- to 6-ton [machines] and CVP55 for 7- to 10-ton [machines], complimenting their current offering of CVP16 and CVP55, to ensure the best match for your machine.  


The biggest enabler for rental is making sure the machine has a coupler to allow for easy change as the job changes. A coupler allows quick change to any attachment without the hassle of wrestling multiple tools to swap attachments. A manual pin-puller is a very economical way to add a coupler on a machine. Parts of the U.S. tend to use a pin-lock style coupler which also provides a lot of versatility, whereas a manual pin-grabber is also another option and matches the pin-on bucket for the machine. However, all three require exiting the cab to change the tool. This is where the hydraulic pin grabber coupler has the advantage because it allows simple operation from inside the cab to swap tools as fast as you need.

The most popular rental attachments align with the same as retail — augers, hammers and vibratory compactor plates.  We offer several different types of brackets that make it easy to add an attachment to a customer’s MHE. These brackets on the attachment can be removed and changed out to allow the same tool to be used on machines with different coupler interfaces, as well as different sized machines. Some of these include pin-on/pin grabber coupler, pin lock coupler, pin-puller coupler, S-Type coupler and CW coupler.

What are some of the unique and infrequently bought or rented attachments that you think contractors would benefit from learning more about? Niche products so to speak.

One of the unique attachments on Mini Hydraulic Excavators would be Cold Planers. Typically, when you think of a cold planer attachment, you think of a skid steer loader (SSL), but having this option on a MHE allows the ability to use the boom and stick to get into some areas that you wouldn’t be able to fit an entire SSL machine. Cat has two new models: the PC35 for 5- to 6-ton machines and PC45 for 7- to 10-ton machines. An operator can also utilize the stick steer and cruise control features on their MHE for easy operation with this attachment.

Rippers are another unique one that you don’t think of often but are actually pretty common. They are built to cut through dense dirt, loosen rocky soil and break below the frost layer. We have a few different size ripper models designed to fit the customer’s MHE machine for those tackling some challenging ground conditions needing ripping power.

Mulchers and flail mowers are also excellent tools when trying to remove vegetation in overgrown areas. Mulchers can turn trees, shrubs and saplings into mulched material. Flail mowers work excellent on MHE machines when needing to mow and clean up along hard-to-get areas such as ditches, fence rows and high slopes.

How do contractors who own compact excavators decide whether to buy or rent an attachment? In other words, how many jobs does it take to justify full ownership and the purchase price?

Caterpillar’s 306 CR

There is no single answer to this question, this one widely depends on the type of attachment and how frequently it is being utilized. However, owning an additional attachment besides just a bucket allows the customer to be more versatile with their machine, expanding the capabilities and types of jobs that can be completed. The owner will need to evaluate the amount of work and additional income they would receive by adding a specific attachment to their portfolio. It’s always an option for those wanting to start out as entry, with minimal investment, to first try out with a rental attachment to see how much more work they are able to develop and then move towards leasing or purchasing the tool. Any purchase is an investment, and deciding whether to lease, own or rent, is also part of the equation for the customer to determine what is best for their return on investment. One advantage to keep in mind is that when you purchase a Cat attachment for MHE machines, including all hydromechanical tools, it comes standard with a two-year warranty.

Most compact excavators are sold with a standard bucket. What types of non-standard buckets are contractors buying or renting and for what kinds of jobs?

Besides just your standard digging buckets, Cat also offers tilting ditch cleaning buckets, grading buckets and Nordic style buckets, to name a few. Ditch cleaning buckets are for cleaning wide trenches, loading materials, slope-cutting, grading and finishing work in construction, landscaping and road maintenance applications. Grading buckets help customers with their finish work as well as grading, trenching and slope-cutting. Nordic style grading buckets work well with the Tilt Rotate System (TRS). The rear corners of the bucket are tapered so you can get into tight areas and corners. Many of our Cat buckets also have the option for a bolt-on cutting edge or bolt-on teeth which can easily be replaced and extend the life of the attachment.

The Cat Tilt Rotate System (TRS) can tilt 40 degrees left/right, and has 360 degrees of bidirectional rotation, allowing the operator to manipulate the bucket in various positions. It is perfect for excavating at any angle/direction, without having to reposition the MHE, improving efficiencies in landscaping, water and sewage and other applications. That being said, our TRS is best suited for a customer wanting to own the attachment themselves, fully integrated with their Cat machine. The one-time machine setup requires installation of advanced joysticks with additional rollers for the added positional functionality, while the TRS is easily removed, it’s not a tool you would swap around different machines in a rental yard. There are three models, TRS4, TRS6 and TRS8 for MHE machines ranging from 3 to 10 tons. The TRS only requires first aux from the excavator, and you can also easily swap out the bottom attachment if you’re looking to use multiple buckets or hydromechanical tools such as the new G206 and G208 multipurpose grapples.

How does a contractor make sure he has enough hydraulic horsepower for an attachment?

A lot of people focus on flow only but keeping things in mind like pressure (which is part of the equation for hydraulic horsepower), and weight are important specifications to know. The best tip for this is to choose the attachment that is best fit for your specific machine. Cat offers many different attachments, and they are designed to be optimized for the size, weight and hydraulic capability of the customer’s MHE machine. For example, Cat has 17 different B model hammer sizes and six H models to fit the full range of 1- to 10-ton MHE machines for whatever needs you have. Pairing the correct attachment with the customer’s machine will ensure maximum productivity for the operator.

What attachments work with two-way hydraulics and which ones require three-way hydraulics?

Cat micro excavator

The type of attachment being used will determine whether one-way or two-way hydraulics are required. For example, when operating a hammer, CVP, cold planer, mulcher or flail mower, you will want to ensure the machine is in one-way flow to avoid back pressure. Tools that require two-way flow are augers, thumbs, scrap shears and tilting buckets for a MHE. An often-overlooked feature of Cat MHEX or backhoe loaders is the changeable one-way/two-way valve to reduce all back pressure on those one-way flow tools.

What are some important operational and safety tips for using attachments?

  • The most important tip is to always be aware and cautious of your surroundings. There could be nearby workers or obstacles such as power lines causing a safety concern. When using attachments such as mulchers, hammers and flail mowers, it is extremely important to keep an eye out and make others aware to keep a safe distance, since material can fly unexpected distances and directions.
  • A quick walkaround of your machine will help you look for any leaks, unexpected obstacles or broken or damaged parts.
  • For hydromechanical tools, it is important to check that all hydraulic lines are correctly hooked up, tightened and checked for no leaks.
  • The operator should always use three points of contact when entering/exiting the machine and wear a seatbelt for their own safety.
  • Before operating, ensure every attachment is properly secured to the machine when using coupler and apply down pressure to double check.
  • Depending on the tool, the operator might need to adjust the aux flow to optimize the performance. This can be done quickly through the monitor display.
  • Upon finishing the job, make sure the machine is parked in a safe location and that the attachment is grounded with all pressure relieved.

Is training on certain attachments available at dealers and rental houses?

Caterpillar PL161 Attachment Locator

Anyone is welcome to reach out to their local Cat dealers for more information on MHE attachments and training available. Their priority is to help the customer to ensure they get the work done and in a safe manner. There are also many videos online highlighting attachments for MHEs and showing operating tips. No matter the job, Cat has the solution you need for your MHE.

Pam Kleineke is managing editor of Compact Equipment.

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