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Cover Story

Table saws

There are few jobs where you don't have to cut and fit the units you are installing. When the cutting gets to be intensive, turn to the classic "table" style brick saw in contrast to the high-speed handheld. Productivity will improve, and so will morale.

Did you ever see a mason or laborer with the side of his or her boot cut by a handheld high speed saw? Workers sometimes get a little over confident — or careless — and try too many cuts, too fast, and too close. It doesn't happen often, but once is too many.

The answer is, of course, use a brick saw, the table-mounted saw that can provide accurate, safe cuts time after time after time after... well, you get the idea.

The staple of the mason, the brick saw hasn't changed much in decades. They have gotten better, more accurate, longer lasting, and now offer features to make them even more productive. But they are still whirling blades held in a movable arm, mounted on a cabinet with a shuttle to move the brick or block into cutting position.

If you haven't evaluated brick saws for a while, you might be surprised how many new features they offer the mason. The key is options: the more the vendor can offer in features, standard or add-on, the more work you can do with the equipment.

Take the power unit, for example. Brick saws are used in harsh environments, with dust and slurry common, and must be constantly working to earn their keep. According to Royce Brock, masonry superintendent at J. E. Dunn Masonry, Kansas City, Mo., "The first consideration in choosing a saw is the availability of power. You have to have power to run the saw and every job is different." Table saws

Vendors match that need with a variety of power units, both electric motors — in multiple voltages — and gasoline engines. You might think the best choice would be the gas unit, a self-contained power supply. "In our industry, that means a Honda engine," says Andy Lundberg, product manager for masonry saws at Target, a division of Diamant Boart, Olathe, Kan. "With the gas unit, you run the saw from the engine — it's not a generator that provides power for an electric motor. Or you can opt for a combination unit where the gas engine can be swapped out for an electric motor in about three minutes. We have customers that buy four or five saws, all with electric motors and maybe one gas unit. Then if the job is too far from the electric power, they just take the gas unit along, swap out the motor for the engine and start cutting. Same saw, more choices." Gas-driven saws generally can't be used indoors due to air quality issues and noise factors.

Electric motors are more common and here again, there are choices to make. Lundberg explains, "If you are going to be cutting brick all the time, you don't need a five horsepower motor, a 1.5 or 2 horse is sufficient. If you are only working in residential areas, pick a 1.5 horsepower, 110 Volt motor; it's adequate. But if you know that 220 is going to be available sometimes, get a dual-voltage unit where you can switch from 110 to 220 by throwing a switch. Usually, 220 runs more efficiently but watch your extension cord — the wrong size for the length of the run will cut the available current."

The current draw of the saw varies from start-up to continuous run. When you use a portable generator, for example, to run the electric saw, be aware that you might have to use an over-rated generator. MK Diamond Products, Torrance, Calif., makes multiple lines of masonry saws. Their literature states: "These motors require approximately two to three times the normal running requirement for startup. For example, a saw motor with a stated power requirement of 1426 watts and a startup factor of 3x the normal running load will require a generator rated at approximately 4278 watts."

In addition, if a water pump is being used with the saw, this will increase your startup load approximately 138 watts for a total of 4416 watts. Another factor that must be kept in mind is that the normal running requirements are a baseline rating and are easily exceeded if a motor is placed under a greater load (i.e. pushing a thicker material through the saw at a faster rate).

Wet or dry?
If time is money, and it is, then you want to cut and place masonry units as fast as possible. That means cutting dry and that means dust. Everywhere.

Brian Delahaut of MK Diamond Products says, "One concern masons have is that they have to let that water dry off a brick or block; they can't go right from the cut to putting it in place. With dry cutting, because you don't need water, you can just cut and place, cut and place." Table saws

And, he adds, "A lot of the materials supplied today have a tremendous amount of acid or coloring or other types of materials in them. The more you cut these products wet, the more the concentration of the chemicals will be in the water in the pan. What ends up happening is you can get a staining action on those units as the day goes on, making those bricks or blocks look different than the ones you started with in the morning. Many engineers are calling out in the specs that they don't want any of the materials cut wet, only cut dry. But with silicosis being a big issue, you must remember that wet cutting will decrease the dust from the bricks or masonry block."

Wet is messy but healthier, it seems. As Lundberg says, "Slurry is not as big a problem. Wet sawing minimizes airborne particles. Slurry goes down into the water pan and it can be collected and disposed of safely. The problem with cutting brick and block dry is the inhalation of the dust. When you cut dry, you've got to be able to filter out all that dust to keep it from workers lungs. The contractor is supposed to be sure everyone on the jobsite has dust protection. But when you cut wet there is no dust."

Brock, the mason super at J. E. Dunn, agrees that wet is better. "I'd rather cut wet, to keep the dust down. Architects are getting away from that, not letting me book wet units. That makes it a lot more difficult — we end up having to cut a lot of units dry because of the specs."

Another reason for cutting wet is to extend the life of the blade. Keith Branoff, Detroit area sales representative for Diamond Products of Elyria, Ohio, explains it this way. "The value of a wet application is that you'll extend your diamond blade life, anywhere from 20 percent to 30 percent by adding water as a lubricant and also as an agent to flush out the dust. All saws in a masonry application today come with a water hookup. The downside to the water is that it's messy. In northern areas, in the middle of winter, it's next to impossible to get a mason contractor to use water. For indoor work, you would have to go with water to keep the dust down so everybody would be able to see what they're doing inside of an enclosed area."

MK Diamond makes this additional distinction: "Dry cutting blades require sufficient airflow about the blade to prevent overheating of the steel core. This is best accomplished by shallow, intermittent cuts of the material along with periods of "free-spinning" for several seconds to maximize the cooling process. For wet cutting applications, liberal amounts of water act as a coolant to support the cutting effectiveness and longevity of the wet blade."

Picking the blade
Besides the lubricating effect of water on the blade, picking the right blade for the job, whether wet or dry, is important. Lundberg notes, "You've got to decide if you're going to cut wet or dry. Today, you can cut wet with a dry blade. It used to be all the blades were wet cutting but now we can laser weld segments on to the core that allows you to cut dry."

Diamond cutting disks — blades in other words — come in many sizes and special materials much like the bricks and blocks they are designed to cut. "You have to select the blade based on the material you are cutting," comments Branoff. "If you are cutting block, use a straight block blade; brick, a straight brick blade. Block is softer to cut, is more abrasive and we recommend a harder segmented blade to resist the wear that abrasiveness causes. That way, you'll get a longer lasting blade and save money." Table saws

Brock of Dunn Masonry will occasionally use a combination blade, a compromise for cutting either brick or block. "It's usually not as good as a specialized blade but if you only have a few cuts and a mix of units, it saves time and effort to use a combination. That way you don't have to change blades to accommodate a few cuts."

There are disadvantages to that, however. Branoff explains, "The downside is, if you end up cutting a lot of block with a combination blade, that blade is going to wear out prematurely. It just isn't designed for the abrasive nature of block."

The blade itself is a metal core — disk — with a segmented edge that is coated with synthetic diamond crystals. It isn't a true "blade" in the sense that wood and metal cutting saws use the term. "We're not required to have a full-blade guard, for example, because diamond blades and abrasive blades are in the category of grinding wheels, not cutting wheels," claims Lundberg. "We only have to cover 180 degrees. If you have cutting blades, like on a wood saw, you have to cover 100 percent of them. But diamond blades are grinding wheels — it's actually using little chunks of diamond to grind away the brick and the block. That means you don't have to have 360 degrees of protection."

Delahaut expands on that, "A diamond blade doesn't really cut, it grinds material through friction with the synthetic diamond-bonding matrix. The diamond crystals, which are often visible at the leading edge and sides of the rim or segment, remove material by scratching out particles of hard, dense material, or by knocking out larger particles of loosely bonded abrasive material."

This process eventually cracks or fractures the diamond particle, breaking it down into smaller pieces. As a result, a diamond blade for cutting soft, abrasive material must have a hard metal composition to resist this erosion long enough for the exposed diamonds to be properly used. On the other hand, a blade for cutting a hard, non-abrasive material must have a soft bond to ensure that it will erode and expose the diamonds embedded in the matrix.

Matching the blade to the saw motor capacity isn't as critical in brick saws as with some other applications. Regardless of the horsepower of the saw motor, almost any quality blade will work. "The only real exception," says Lundberg, "is when you are cutting refractory brick. They can be very hard and require a special blade, often best used on a higher horsepower saw, something in the 5 hp to 7 hp range in electric and 13 hp in gas. They'll work on the common 1.5 hp to 2 hp saw but cutting won't be as fast."

Yes, size does count
As with so much, compromise is the key to picking the size (diameter) of the blade. If you are cutting one type of unit, there are blades designed to do that without compromise.

Contractors will often buy the 20-inch saw and use it with a 14-inch blade for cutting brick and switch to the 20-inch blade for block so they can cut the block in one pass. As Lundberg says, "It's crazy to use a 20-inch brick blade with the ability to cut 8 inches deep when you only need to cut 2.75 inches deep. You've paid for all that depth capability — and the diamonds on the blade — but aren't using it. Stock 14-inch brick blades even if you buy the 20-inch saw."

However, that's not a universally accepted practice. Offering a counterpoint is Delahaut: "The problem with a 14-inch blade on a 20- or 24-inch saw is that the rpm will be reduced significantly. This is not a good thing for a diamond blade that is designed for 3,800, not 2,270 rpm. The speed drop is significant enough to cause the blade to be ineffective or to glaze over, something that happens all too frequently."

Some contractors will do this so that they don't have to have two saws, both 14- and 20-inch models. This does not mean that they are using the tool the way it was designed. "In most cases when a contractor does use a 14-inch blade on 20-inch masonry saws, the performance of the blade is called into question and the manufacturer is contacted to address the issue. Maintaining the correct speed is critical in any application."

Blades are designed to run optimally at a certain surface speed, expressed in feet per minute. While you can use a 14-inch blade — or even a 12-inch blade in an emergency — on a saw designed for a 20-inch blade, as Delahaut says, the result can create problems. If you are going to use a 14-inch blade on a 20-inch saw, changing out the pulleys to match the specific rpm is a must. Most manufacturers will specify the right size pulleys and belt combination if you intend to use a 14-inch blade.

Lundberg explains why. "When you put a smaller blade in a 20-inch saw," he says, "it runs at a slower surface speed. With a diamond blade that makes it act Œsofter.' It will actually cut very nicely but wear out much faster than a 20-inch blade in the same application. Still, why buy a 20-inch blade, and pay for all that extra cutting depth, when you only need to cut 2 inches deep?"

Since the saw itself is a long-term investment — some contractors are using saws that are more than 20 years old and still functioning fine — while the blade is a disposable element, over specifying the saw can be a smart move. Over the years, with the variety of jobs a contractor might take on, having the largest, highest quality saw available can be a cost savings. When many saws are purchased, picking a variety of sizes and motor configurations would be reasonable. A smaller contractor might benefit more from the versatility of the 20- to 24-inch saws now available.

Lundberg adds, "A saw is a long-term investment but the blades, they're a commodity. You want to get the best blade with the longest life you can get. Many masons are using handheld high-speed saws to cut brick — I know some companies that will have 25 high-speed saws, and no or only one brick saw. If you get 14-inch blades for those handhelds, they can also be used on your masonry saw. Typically they don't have as good a life, but you don't have to buy 2 blades."

It's all in the wrist
The brick saw is accurate and that accuracy is highly repetitive because it is a stable platform with precision components. The masonry unit is held on a moving shuttle that allows the worker to align the unit with the blade for an accurate cut. But in some ways, that simplicity has made a difference in how the saw is worked.

Delahaut recalls, "The action of the worker should be cut, pull, cut, pull. It's a technique that, in many cases, has become a lost art. In the 50s, they had to do that because the blades were designed with a brazed bond that held the segment on. You couldn't have the blade in the masonry material too long without some cooling action. That action was removing the material from contact with the blade for a beat or two.

"Welded blades became the norm in about 1980," he continues, "and laborers who use table saws don't have to worry as much about this process of step cutting. They can lay the blade in the cut longer. Still, the table is designed so you bring the material in to the blade and you're able to rock it back and forth. You'll see that a good mason knows that technique, and the laborers will figure out that the blade will cut more efficiently."

What's new and coming?
Things change, even in an industry as old as masonry. New technology won't make a revolutionary change, but there will be some incremental changes in the durability and performance of the tools of the trade.

New motors are being examined for use on brick saws. "I just came back from a meeting with Milwaukee Electric Power Tool," reports Delahaut. "There are some new motor developments they're beginning to explore that will be available in the next few years and we'll have to decide if they are applicable in terms of moving a diamond blade. There are technologies that will reduce the cost of the diamond blade, improve its performance, provide more reliability to the customer, and will allow the blade to be lighter weight. Those are all things that we have to wait on while we see what the motor developments are. It's all based on the torque, speed and efficiency of motor design to limit the amount of electric power that's being drawn. On a job site, that is the most limiting factor."

Changes in blade design have made them quieter, a consideration both indoors and out. Blades whine. The wind whistling through them makes a high whining noise. "It's irritating and loud," acknowledges Lundberg. But there are answers. "If you hit the core of a normal blade, it dings like a bell. If you hit the core of Target's Silent Runner blade, it's like hitting a piece of wood. It cuts down the noise by close to half."

It's more expensive to make a quieter blade, obviously. "We put it only on our top blades," admits Lundberg. "This core is so expensive, you can't use it on an inexpensive blade because your starting cost is too high. It's been most successful where people are cutting indoors all the time, such as in the marble and granite fields, and on larger jobs where there are many other workers around whose hearing could be affected by the noise."

Other blade companies are following suit, bringing out silent core blades to ease ear strain on the job. It's all an evolutionary process but it increases the benefits to the contractor and, as volume goes up, will likely bring the costs down to where they are for other high-quality blades today.

Why the table saw?
In a word, accuracy. Dunn Masonry's Brock adds, "Besides the accuracy issue, there is the benefit when you have large quantities of units to cut. If you have a large quantity, you want to use the table saw. And here I mean quantity as in hours per man a day. If a man was going to cut for an hour on a table saw, it would take a couple hours with a high-speed handheld. If you were going to cut 10 minutes in a day, you'd probably do it with a high-speed."

In application, the brick table saw provides an easy to use cutting tool that can repeat accurate cuts over a large quantity of masonry units. Lundberg explains, "You need to cut straight, and it's easier to cut straight if you have a flat table and you can slide the brick or block against the backstop. You're square, then you plunge the blade down perfectly perpendicular into the brick or the block, or slide it through the brick while sitting perfectly square on the table. If you have to cut 50 in a row, it's a lot easier to grab one, put it up, slide it through and keep doing that one after the other in an assembly line fashion than it is to step on a brick, try to cut it straight, walk down the row, making perpendicular cuts with a high-speed handheld."

And it will save those occasional boot-cutting accidents, too.

No dust or slurry?
It seems logical at first: if dust is a problem when cutting, why not use a dust collector — in other words, a vacuum cleaner — to remove the dust? Sometimes logic runs into conflict with practical, however. Water spray has been the norm for dust control and most table-mounted brick saws use this method. Still, the vacuum cleaner idea persists in coming up in conversations among masons.

One company does offer a vacuum attaching point and a dust-collecting channel on its table saws, making it somewhat unique in this market. EDCO, Frederick, Md. produces a line of what it calls hardscape saws designed to cut the hard paver-type bricks used in landscaping and integrated into driveways and walkways. Using gasoline engines or electric motors, the portable table saws provide a vacuum tube that brackets the blade at the point of cutting. The user connects an outboard industrial vacuum — a shop vacuum will do nicely — and cuts away.

EDCO claims that there is a small puff of dust at the beginning of the cut and then the vacuum draws the remaining dust away from the work and into the canister. An obvious benefit to this approach is that, with no water spray, there is no slurry and much less mess. OSHA is reviewing this as a viable option for dust control although at this time there has been no comment made as to its effectiveness and acceptance by that agency.

Will the hardscape saw work equally well for common, face and other brick? According to Chuck Hommey of EDCO, "The saws work best on any solid material as the material becomes part of the vacuum channel, improving the dust pick up."

He adds, "While using water will eliminate the dust problem, the vacuum system lets you cut dry and still remove 95 percent of the dust."

A graduate student at the University of Washington Department of Environmental Health did a dust and silicosis study on the EDCO GMS-10 (10 inch saw with vacuum attached) with satisfactory results and the National Institute for Occupational Safety & Health (NIOSH) indicates the personal exposure limits (PELs) for the saw are very low.

So if dust is a problem when cutting dry — and you must cut dry — try vacuuming it all away instead.



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