Grading and Excavation Contractor

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There are graders to achieve the level of accuracy you need.

By Paul Hull

If you talk with experienced grader operators you’ll find an encouraging confidence in their ability to achieve fine results with their grading. They acknowledge the advantages developed by manufacturers but they would still like you to recognize the operator’s skill. And that is well justified. An efficient grader operator is a joy to behold. The operator of what looks like a rather awkward, large grader can get remarkable results … as long as he (or she) has room to maneuver and the time to make several passes at the problem. When contractors and operators talk about fine grading, they do not usually mean what you see on most county roads and in the preparations for extensive highway projects, even though the accuracy of the grading for those assignments can, indeed, be fine.

It never fails to shock people just how accurate graders can be. They do seem to be awkward machines (even relatives of those alien invaders we sometimes see in science fiction movies) but, in the right hands, they can be amazingly accurate. When you see a lumbering giant grade the surface to fractions on an inch, you appreciate how much skill has gone into their design, manufacture, and handling.

The most popular graders for fine grading tend to be the compact versions, because much fine grading is scheduled in areas with restricted space–places like parking lots, the forecourts of gas stations, between houses where the space is only 10 feet wide, or as the final step before concrete for slabs inside new buildings. To work in restricted areas, the grader must be able to have access, be able to maneuver, and be no risk to surrounding structures.

The Cross Blade, for example, is a compact grader, made in Spokane, WA, by hMACH (a company whose name may be unfamiliar to you, but has a history of 60 years of specialized design and manufacture, associated with such company names as R.A. Hanson and The Factory Co.). “Nimble” is a word used by Miller Griffith, sales and marketing manager for the manufacturer, to describe the Cross Blade. “Its profile is only 14 feet 6 inches, and that makes it ideal for small lots, parking lots, areas with obstructions like islands, and all those sites where the bigger models (at 21 feet) can find maneuverability difficult and slow,” observes Griffith. “It’s easy to transport with no need for a low boy.” Most purchasers of this compact grader are contractors and they view it as a specific tool for specific jobs. Significant features are its short wheelbase (10 feet 5 inches), overall width (7 feet 8 inches), compact turning radius (8 feet 6 inches), a tilt of 38 degrees, cutting depth of 7 inches and side shift of 38 inches. The width of the moldboard is 10 feet and Griffith points out that the ability of the grader to push a loaded moldboard of that size bears witness to the strength of the machine. It uses a CAT 3054 Turbo–Tier II diesel engine, with 100 horsepower. It weighs 13,000 pounds; it does not jump up and down when working. There are several options available, of which the most popular is the dozer attachment. “There are more than a hundred attachments available, thanks to the Quick Attach,” notes Griffith. “We only offer four or five that are most appropriate to the kind of work our customers do, but a user could add all kinds of attachments if they suited his needs.”

You’d have to include The Maintainer in this group. From Huber Construction Equipment, it’s been around for many years. It is not the most curvy or colorful machine, but it is eminently practical. The manufacturer claims it does the work of five machines (grader, dozer, scarifier, side dozer, and loader) and “it can do about 75% of all jobs given to graders.” With its compact size, especially its narrow profile, it can get into confined areas and maneuver steadily where bigger machines cannot cope. The hydraulically controlled moldboard is 9 feet, with 38-inch angularity and 19-inch power sideshift control. The operator can position the blade from 9.5 inches below grade to 13 inches maximum clearance. The power slide lets the operator keep the blade plane and angle while extending or retracting up to 19 inches to work around posts, culverts, and other obstacles.

Productivity and Accuracy
As soon as we describe grading as “fine” we tend to talk about accuracy rather than productivity. Both attributes are essential to good fine grading. We must achieve the levels required, and fast. One of the surprising facts gleaned from many conversations with grading and excavation contractors is that only a small percentage of them seem to use technical assistance on the job. There are available instruments (technologies, if you will) that can avoid the expense of too many passes, the cost of having to do the job twice. At random, we looked at three companies who provided such help for contractors.

Trimble has many instruments and systems that can help people in the construction industry, from 3D machine control and guidance systems to conventional grade control systems. The latter group includes the GCS600 (= GCS for Grade Control System). There’s one version for excavators and another for graders. The one for graders is described as a flexible, cross slope and elevation control system designed to be used on graders for fine grading work. Where has it been successful for contractors? They have used it on road construction and maintenance, for runways, for road ditches and embankments, and especially for housing and building site pads of all sizes.

The Trimble GCS600 uses two AS400 angle sensors and one RS400 rotational sensor to calculate the cross slope of either side of the blade, as well as an LR410 laser receiver or an ST400 Sonic Tracer too give elevation control. If you use the ST300, you can get stringline, previous pass, or curb and gutter tracing. With one or two LR410 laser receivers, you can use the system for fine grading plane surfaces. This GCS600 has been described as “excellent for applications where you have tight tolerances and for finished grade work”. If you acquire a CB420 Control Box with the GCS600, you get software with a comprehensive range of features designed particularly for lift and/or tilt control on motor graders and dozers. Does all that sound too technical for a contractor like you? Believe this. There are many contractors less smart than you who are using such instruments to make their grading jobs more profitable.

Another leader in the instrument field is Topcon. You would probably agree with this manufacturer of sophisticated instruments that nobody will buy or use something that is difficult to understand and work. For most of us, complicated inventions quickly lose their appeal. The Motorgrader System 5 from Topcon claims to be the easiest to understand grade control interface. (Don’t ever underestimate the value of a well-trained local dealer when you consider technological investments.) System Five has one control box, four sensors, and a “High Flow” hydraulic valve package that work together to determine the blade’s position and generate signals that will keep the blade on grade. Reduced grade costs and improved productivity are what the System Five promises, whether your work involves flat or sloped surfaces, roads or airport sections. Topcon stresses the ease of operation of their products, saying you get superior machine control with less effort. Each control box has a large, bright LCD screen with intuitive controls “so that a novice operator can work like an expert.” (One of the attractive points of good machine control systems is that they enable a contractor to hire operators who lack some skill and experience. In these times when skilled, motivated operators are not easy to find in many places, that can be a plus.)

At Apache Technologies, we find several instruments that could be useful to grading and excavation contractors, including the Bullseye 5+ laser receiver. This aid, used for both grading and excavating efficiency, has a blade tilt indication built in, so the operator of the grader can keep the blade level. It can be programmed, too, to match an existing or known grade for slope matching operations. Center On-grade provides the same amount of grade data above and below “on-grade”. A step above that model is another from Apache. The Tornado F1 gives automatic blade control for you to save time, labor, and materials on every grading job, rough and fine. The operator can switch from automatic to manual control with just a quick flip of a switch and can adjust (from the cab) the accuracy of settings and the hydraulic blade speed. The dynamic blade balancing is set during installation and gives you a smooth raise and lower response. Some of the Bullseye receivers can be moved to backhoes and excavators when their job on the grader is done. The laser receiver is mounted above the cutting edge of the blade (grader or dozer). The control box and a hydraulic installation kit are tied in with the machine’s hydraulic system. The grade information from a rotating laser is processed and that’s what automatically directs the machine’s hydraulics to maintain the desired elevation of the blade.

There are other reputable manufacturers, too. Do a little homework. Check among the advertisements in Grading & Excavation Contractor, check the Internet, and then check with local dealers mentioned by manufacturers. Are there other contractors in your community who use similar instruments? Do they work well? Is the after-sale service good? To ignore today’s laser helpers just because “anybody knows they couldn’t do what they claim” is rather like saying that computers will never be successful in real businesses or that the automobile will never replace the horse and cart. These instruments are aids. They help good operators become even better.

The PowerBlade machine control system from Leica Geosystems is designed in a kind of building-blocks configuration, but that’s its only resemblance to anything childish! The system is adaptable to budgets of different levels; that is why you can build it with increasing units of sophistication. It works well with all types of blades and machines in grading, including dozers and scrapers. Start with the MLS700 Laser Sensor and you have an easy-to-use, accurate, and tough laser sensor with which your operator can see readily visible LED grade displays. It’s tough because it works in all weathers, while the LED aspect means the operator can see the display in all lighting conditions. With a little extra, your budget will allow you to use the MCP700 Panel and a hydraulic valve package that saves you time with automatic grade control. Add the MPM700 Electric Mast and you can get easy grade changes from the cab, as well as excellent land-leveling functions to manage the most complicated projects. At the recent World of Concrete one of the most popular sites was where Leica Geosystems showed its GradeSmart 3D simulator, a 3D video where attendees could sit in the operator’s seat of a dozer while the system completed a grading project. It was like being at a real job site when you were only sitting inside a comfortable exhibition booth.

Sourcing Your Equipment
There are some well-known and respected makers of motor graders. Caterpillar, Volvo, John Deere, Case, Komatsu, and New Holland spring to mind. There are also manufacturers who are less well-known, not necessarily inferior. This concept probably applies to all construction equipment, to all equipment in any industry, and it does not demean the leaders in a sector to recommend that potential users investigate other, less publicized sources. At a project last year where a contractor was repaving the forecourt of a gas station, with restricted space and sensitive neighbors to make maneuverability a challenge, none of the grading or paving equipment bore a well-known brand. I asked the operators about the compact grader and the small paver and they said they had used them for years and they were “perfect for this type of job." The same contractor does many highway projects; using big, well-known graders and pavers for that.

Three models of graders from LeeBoy range in weight from 7,880 lbs to 25,300 lbs. The smallest of these (635B) has won acclaim for its suitability in specific applications. A construction contractor had been used to a heavily manual technique for setting the floors for those boxlike structures where the area was about 30,000 square feet. The company loader would dump dirt and crews with shovels would go in to grade the dirt, set up stringlines, and all those popular methods of yesteryear. The contractor bought a LeeBoy 635 grader, with laser tracking controls. The old method could take three to four weeks for the floor of a 30,000 square foot building but, with the new, compact grader, it became a three or four day job. Why the improvement in productivity? “If you had a larger grader for this size job, you couldn’t move around with all the other things going on,” explained Tim Fosha, the shop foreman for JD Construction of Henderson, NV. “LeeBoy is not the only company that makes a grader that size, but they were the only one that made one, and our dealer had it available when we needed it.” The 635B, LeeBoy’s smallest grader trio, offers an 8-foot sliding moldboard, center-mounted scarifier and two-speed hydrostatic drive. For contractors, it has proved to be the right size for the right job.

Do you have a skid-steer loader? Have you considered adding the right attachment to make it a practical grader? Ask your skid steer manufacturer/dealer if they recommend anything appropriate. One to consider is the Mini-Might Patrol. It attaches to all major skid steer loaders and comes from Equipment Resources, Inc. Built of T-1 steel, with a seat safety shutdown system, this attachment offers an 8-foot cutting blade and an oscillating front axle. The blade has a 56-degree swing. Among options for the Mini-Might Patrol are a 10-foot blade, 24-inch blade side shift, a laser leveling system, an 8-foot slope board, and a front-mounted scarifier with three or five teeth. For this manufacturer, in Missoula, MT, the grader attachment has been a development from fabricating successful equipment for the logging industry. Who buys a Mini-Might Patrol? Contractors, especially paving contractors who have parking lot, driveway, and similar small projects to complete quickly and efficiently.

This is not established by published reports or research but I have read and heard that tracked loaders (with the appropriate attachment) are becoming increasingly popular for fine grading on smaller projects, such as residential sites, and at hospital parking lots, school grounds, and service stations. Their size and maneuverability are, again, key benefits, and many contractors can use a tracked loader for much more than fine grading, keeping it busy where a dedicated grader may not be.

Smaller graders are used frequently for the jobs on large projects where larger graders could not maneuver well.

The “big” manufacturers don’t only make big machines. For the 670D, a compact grader from John Deere, you can order an integrated grade control (IGC) package and have it factory installed to have a cleaner and easier installation of Topcon and Trimble auto grade systems. There’s less likelihood of hydraulic contamination if you have it installed that way. The 670D also offers Precision Mode. With that, operators work in front-wheel-drive in first to third gears, and a 15-position rotary dial fine tunes front-wheel speed, allowing the machine to move as slowly as one-quarter mile per hour when working around structures and curbs. Its wheelbase is 20 feet, 1 inch, and its turn radius is 23 feet. The moldboard is 24 inches high and 12 feet wide (it can be longer).

One use for this machine is for finely graded roads to a sawmill in Argentina. “I like the controls. They are smooth, compared with some competitive models we tested,” says operator Luis Astudillio. “In 550 hours so far, we have experienced 100% uptime and plenty of productivity. One thing I really appreciate is the clear view of the blade.”

Control
The manufacturers of graders publish detailed information about their machines and there are always features or benefits that grab one’s attention. Volvo (with seven models in the G900 Series) has introduced the industry’s first 11 speed transmission. This HTE1160 is optional on all the models. One of its important benefits is that, with 11 speeds forward and six in reverse, it will allow slower ground speed for fine grading applications. Shuttle shifting on Volvo graders allows straightline, forward to reverse shifts (and vice versa) without the operator having to use the inching pedal or stopping first. That reduces cycle times and helps reduce operator fatigue. “Demands for precise grade control to meet the required grade spec, and the fact that highly skilled operators are hard to find or retain, have been drivers for the designs of the modern motor graders,” comment Brian Lowe and Gary Atkinson at Volvo Motor Graders. “Precise control of the motor grader extends beyond the actual levers the operators use to position the moldboard. All of the systems and design elements of a motor grader must work in concert in order for the operator to be the most productive and be able to produce an accurate finish grade.”

Skilled operators have told Volvo that the eight levers that directly impact the grade must be easy to access and positioned in an industry standard arrangement. The relationship of the levers to the steering wheel is important because operators don’t want to take their eyes off the work area when making critical moldboard positioning or steering adjustments. This does not only apply to finish grade operators, of course, and is practical for those responsible for rougher applications like site preparation or over burden removal. “From the placement of the transmission in the grader frame to the design of the blade lift system, the entire grader must be designed as a whole and not as a series of parts,” advises Lowe. “For instance,” adds Atkinson, “Volvo positions the transmission ahead of the final drive, which, in addition to increasing blade down pressure and front end weight, keeps the front wheels from sliding around.”

Among the smallest of Caterpillar’s range of motor graders, the 120M offers an innovative method of joystick control. CAT calls it Intuitive Steering Control and points out that it creates a direct relationship between the lean angle of the joystick and the turning angle of the steer tires. The joystick is held in position by a brake tensioning system until the operator moves it. There are seven functions for each joystick (left and right) with a return-to-center feature that returns the machine to a straight frame position from any articulation angle. The right joystick controls primarily the drawbar, circle, and moldboard functions; while the left joystick has primary control of the machine’s speed and direction. It’s worth a visit to Caterpillar’s Web site to see the description of these controls. The 120 M has an optional AWD system. With this, the infinitely variable pumps and motors maximize torque in each gear, delivering, says CAT, the most power to the ground in the industry. The Hydrostatic Mode of the All-Wheel-Drive system disengages the transmission and provides hydraulic power to the front wheels only. The ground speed is infinitely variable from 0 to 5 mph–just right for accurate finish work. Also standard with the AWD is the Steering Compensation System, which permits a powered turn by adjusting the outside front tire speed up to 50% faster than the inside tire. That gives better control, less damage to surfaces, and a significant reduction in the turning radius in poor underfoot ground conditions.

On New Holland graders, the full power shift direct drive transmission with electronic control produces the accuracy desired for fine finishing and grading. Power controls include a main hand throttle that can be overridden by a foot-operated accelerator/decelerator pedal. There’s an inching pedal available for precise grading and accurate movement in tight areas. The standard New Holland five-position moldboard saddle angle has been successful for grading slopes and embankments; the 25 degrees of articulation angle (both left and right) gives the grader great maneuverability, visibility for the operator, and control. The tires can lean up to 19 degrees for extra maneuverability.

If we have to extract the main points from conversations with those who use graders, they would include the good reasons for making finished grading as accurate as possible. The most commonly mentioned reason was that correct grading could end up saving a contractor many dollars in concrete expenses, on the basis that, if your slab of several thousand square feet is supposed to be four inches, you will waste many dollars if you make it five or more inches thick because of faulty grading. Fine grading is often the last step before the final finish, so its quality is vitally important. If there are changes in techniques, it seems to be that more contractors are using laser technologies to speed the work and its accuracy, and many of those contractors for whom grading jobs are generally small are discovering the versatility of basic construction machines, with the addition of suitable attachments.

Paul Hull writes on construction topics for several magazines.

GEC - March/April 2008

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