How to Get the Most Capacity out of Your Digger Derrick

Digger derricks are designed to tackle the most demanding of jobs, from transmission and distribution to backyard infrastructure. Whether you’re setting poles or moving material, these five tips can help you get the most capacity out of your digger derrick.

Get Familiar with the Capacity Chart

Altec’s digger derricks are a durable, reliable piece of equipment, but it’s important to stay within the limits outlined on your machine’s capacity chart. Altec offers derricks with 10-foot load ratings that range from 3,800 to 30,000 pounds.

Each machine’s capacity chart includes model and serial number, included options, use type, rated unit capacities and deductions. Load charts are provided by load radius, or the distance from the center of rotation to the load line, as well as by associated boom angles.

Altec’s derricks are equipped with a hydraulic overload protection system (HOP) to prevent conditions that excessively overload the booms. At approximately 110% of rated hydraulic capacity, the HOP system should engage, stopping the functions that increase the overload including winch raise, boom lower, boom extend, and digger dig. The complementary functions are all available to lessen the load on the boom and disengage HOP.

While the HOP does prevent significant overloading, if the system is forced to engage, operators have already overloaded the machine, which can cause excessive wear and tear.

Extend the Upper Boom First

The booms of Altec’s digger derricks are controlled independently, so operators can choose which boom to extend in what order. The upper boom of Altec’s digger derricks are often made of fiberglass and nested inside the steel intermediate boom.

Many operators assume the steel boom is stronger and extend it instead of first extending the fiberglass, but this reduces your derrick capacity. When extending the intermediate boom without extending the upper boom first, the derrick is now supporting the weight of an upper boom that’s not being used. Instead, fully extend the upper boom first, and then extend the intermediate boom as necessary.

Remove Accessories When Not in Use

Accessories attached to the boom reduce the machine’s capacity. For example, a platform with liner reduces capacity by 165 pounds, and an 8-foot material handling jib reduces capacity by 150 pounds.

Even though a reduction of 150 or 165 pounds may not seem excessive in comparison to total capacity, it can be the difference in having to reposition the derrick to complete a job. Removing unused accessories also reduces the boom tip profile when working in congested areas.

Understand Two Parting

When a load exceeds the winch capacity or winch line rated working strength, but is within the capacity of the unit, two parting is required. Check out this short video for more information. Two parting is also explained in the unit operator’s manual.

Consider the Winch Placement

Altec offers digger derricks with turntable or boom tip winches. The winch placement is determined before the truck is built as part of the work order. Boom tip winch configurations typically have less capacity as the boom must support the weight of the winch and supporting structure.

Consider these tips as you approach taller and heavier infrastructure, and don’t hesitate to reach out to your account manager to learn more about Altec’s derrick models and features.