Grading and Graders Doing Their Level Best – Part 2

Nov. 1, 1999

For larger jobs, the GD750A-1 is a motor grader from Komatsu America in Vernon Hills, IL, that weighs 42,000 pounds. It has four-wheel drive and an articulated frame, with moldboard geometry enabling the operator to position the blade 90° to the right or left. “One of this machine’s key features is the torque converter with lock-up direct drive,” notes Jimmy Slavens, vice president of marketing for Komatsu.

It allows the operator to run the machine smoothly by using only a brake pedal. “This function will assist, among other things, in the ease of fine grading because the operator will be able to better concentrate on moving the blade.” As with most of today’s construction equipment, good visibility for the operator has been addressed by manufacturers. Being able to see the blade, front tire, tandem tires, and rear ripper from both the front and side windshields is a benefit of Komatsu’s GD750A-1.

“Rebuildability” is one of the benefits described by Caterpillar regarding its H-Series of seven motor graders (with weights from 27,600 to 36,460 lb.). Motor graders do not last forever, but many owners (especially, perhaps, those funded by the public) have requested machines that are rebuildable. For improved performance, the H-Series can do in one pass what might have taken two or more passes with the G-Series. As aware as all contractors are of the importance of operator skill in grading, Caterpillar concentrated on making the control of the graders as straightforward as possible, with the machine taking the responsibility for some functions of precision that could only be previously managed by the most skilled operators. A perceived shortage of skilled operators is a nationwide problem for owners of motor graders.

Deere says that there has been great interest from owners of rental companies in its new series of dozers, presumably for use by those contractors who need a grading dozer only now and then. Motor graders and dozers are available at Cat rental outlets, too. General contractor Irving Mitchell, who specializes in local residential and commercial work, observes that with grading equipment rental, “You must know what kind of time you will save and what profit you will make if you are considering renting equipment for a specific project. Those companies that can estimate accurately all the costs of a larger-than-usual job can often make excellent profits, but smaller contracting companies should be cautious. It’s as easy to make a big loss as it is to make a big profit on some of these large jobs.” Some general contractors are still wary of undertaking projects beyond their normal capabilities, but others say that the only way to grow the business is to meet more challenges. The grading segment of a larger project can be a key factor in profit or loss. Renting the appropriate grading equipment can make sense for the contractor who has a job requiring equipment he does not own (and that he might not need again for a long time). Counter clerks at rental stores say they are seldom asked for motor graders, but small dozers are gaining popularity as a rental item. For turning loaders and excavators into precision grading machines, our observation is that owners tend to purchase attachments for grading work rather than rent them.

Champion has recently introduced the Series VI in response to extensive customer surveys with impressive improvements in hydraulic response, maneuverability, and blade mobility. “The customer and operator are the most important part of the grading operation and machine design,” says Ron Huibers of Volvo Construction Equipment North America, which manufactures Champion graders. Its new Series VI includes 23 models ranging from 80 to 235 hp and is the fourth generation of graders in the past 10 years.

It features an All Wheel Drive System and the only hydrostatic front-drive option that allows the operator to select two-, four-, or six-wheel drive. With only the front wheels engaged, the grader can finish grade a radius of 1.5 feet at 0 to 2 mph. “This is accomplished by disengaging the tandem drive, which eliminates the tendency to push the grader straight forward,” explains Huibers. “This puts power where it is most effective for fine grading and allows the moldboard to be navigated around the tightest corners without the rear wheel ‘scuffing’ the final grade.”

“On the go” is a phrase mentioned frequently during discussions of the functions of grading equipment. “Not having to stop frequently keeps machine and operator progressing smoothly and productively,” notes Richard Schwartz, owner of a contracting company that manages projects in North Dakota, Wyoming, and Montana, where fast, efficient work is especially important because of the shorter work season.

The three models of the H-Series of crawler dozers from Deere offer a counterrotation usable at any speed and helpful for fast repositioning of the blade on-the-go and overcoming corner-loaded side drafts. The operator need not shift into neutral to avoid stalling or limit the machine’s use to good ground conditions. “Good ground conditions? What are they?” ask contractors and operators who work year-round. On the Deere H-Series dozers, the operator sets the ground-speed lever to the maximum speed desired, and as loads change, the drive train responds to power up and down. On level ground or a 2:1 slope, the driver does not need to cross-clutch or ride a brake because the machine will not freewheel (as a dozer equipped with a torque converter might do).

New Holland North America in New Holland, PA, also has dozers with counterrotation: the DC70, the DC80, and the DC100. These are smaller models designed to give low operating costs and easy servicing. Low-ground pressure versions of dozers offer superior flotation for work on weaker ground. In practice, this means in some states that the contractor can enjoy a longer grading season. New Holland offers eight models, with operating weights from 14,300 to 40,800 lb. and blade capacities from 1.7 to 7.4 cubic yards. The company markets motor graders, too, and makes all-wheel drive available “for really demanding applications.” Setting the blades on New Holland graders is designed to be practical and easy because the power to the blade rams is always maintained regardless of engine speed or hydraulic pressure. Pitch range for the blade is 5° backward to 40° forward. Hyundai Construction Equipment in Elk Grove, IL, markets the H70 for smaller dozing and grading work, with 72 flywheel hp.

“As a world-leading ship builder and steel fabricator and the only industry supplier that manufactures all of the products we sell, Hyundai is better able to control both quality and price,” asserts Bob King for Hyundai. The H70 is another machine available in a low-ground-pressure version.

Users everywhere have acclaimed the advantages of hydrostatic drive, including the fact that the diesel engine is never overloaded. All of Liebherr Construction Company’s (Newport News, VA) crawler dozers have hydrostatic drive to allow them to maneuver with both tracks powered and without shifting gears. Liebherr dozers require little room for turning, are able to vary their travel speed without gears, and can carry out steer movements with both tracks powered. They also counterrotate on the spot. A joystick lever controls all driving and steering functions. In talking with contractors, we noticed that it isn’t so much the power of the grading machine that concerns operators; the ability to get around on the site and move in all directions is more of a necessity for fast and accurate completion of the job. The controls play an important role in this, a fact recognized by all manufacturers in their newer designs. Today’s controls are easy to use, conveniently placed, and require little effort.

Komatsu makes some huge dozers, such as the D575A with its 1,150 hp and a blade capacity of 90 cubic yards, but the D155Ax-5 comes at the lower end of the range. “It includes many of the features found throughout the Komatsu dozer line,” says Ed Warner, Komatsu’s US crawler dozer product manager. “It has a hydrostatic steering system, a dual hydraulic pump system, a resilient equalized undercarriage, proportional pressure controls, and our human-first engineering principles.”

The dozer operator has received good attention from Komatsu and other manufacturers recognizing that ease and comfort of operation can boost productivity significantly. In the past, the frustrations of discomfort and unresponsive controls caused inefficiency and waste in grading jobs, but almost all the operators of grading equipment we met affirm that today’s machines are much easier to run and that their own productivity has increased as a result.