Cut-Off Saws

By David R. Crosby

Specs and Tester’s Tester Comments

Photos by David Sharpe

Long before I became a builder, I used gasoline-powered portable cut-off saws in the Air Force for crash and rescue recovery work to cut through automobile and airplane wreckage and buildings. I left the Air Force long ago, but not the saws. Now I build homes in Santa Fe, N.M., and work with as much adobe, concrete, stucco, and re-bar as I-joists and OSB. My Air Force experience gave me a real appreciation for these tools, so anytime I have to cut concrete, masonry, or steel I reach for one. It also showed me that nobody in their right mind would look forward to using them?they’re loud, expensive, and incredibly messy, whether wet cutting or dry. But when it comes to cutting tough materials, they’re also the best tools for the job.

Test Criteria

I tested four 14-inch-diameter saws for eight weeks with engines ranging from 64.1 to 81 cubic centimeters (cc): the Makita DPC7301, Multiquip Side Winder HS81, Partner K700, and Stihl TS 400. I cut concrete, masonry, stucco, and steel, evaluating the tools for power, looking at switches and balance, and checking for smooth blade-guard operation and easy blade changing. I also tested their wet-cutting capabilities and paid careful attention to serviceability.

Power

Everywhere you look in Santa Fe you’ll find 4-inch-thick concrete slabs, brick and block walls, 8-inch-thick concrete walls, stucco, and steel, so they’re part of everything I do. From cutting out window and door openings and plumbing access to demolishing buildings, these tools play a big role every day.

Concrete and Masonry. Brick, block, and stucco were no match for all four of the tools in this test. The same is true for short cuts in a 4-inch-thick slab; however, the 8-inch concrete wall (where we buried the blades on both sides of a long cut) brought out the tools’ power differences.

The Makita cut-off saw was relentless. With a 73-cc engine, it was fast, smooth, and powerful. While the 64.1-cc Stihl was a little less powerful than the Makita, it performed well in every situation. The Multiquip and Partner tools followed next. They were more reluctant in 8-inch concrete and vibrated more than the other two models. The Multiquip vibrated the most, while the Partner cut the slowest.

Steel: Angle, Re-bar, and Structural Tube. As building designs become more creative, I find I am working with more steel, which overpowers my re-bar cutter and recip saw. Cutting 20-piece bundles of #6 Grade 60 re-bar was no problem for the cut-off saws. As for pipe and tube, it took more time to block it into position than it did to cut it.

Controls, Adjustments, & Balance

The primary controls on cut-off saws are the on/off switch, choke, compression release, and throttle. I looked for them to be easy to reach and operate, and tough enough to take the abuse these tools face.

The Makita’s and Stihl’s controls are my favorites. I could reach and operate them easily, even with gloves on, and they all worked with positive action. The only criticism I have is that they could use a half-choke detent. The Multiquip switches are a bit small but worked fine; they also could benefit from a half-choke detent. Partner’s switches worked well, too, though the plastic made me wonder how they’d do in cold weather.

Blade Guard. The blade guard is the most important safety feature on these tools. It should always be properly adjusted for the angle you’re holding the saw relative to the work, and a good adjustment mechanism makes for a guard that workers will actually adjust (in my experience) rather than use the saw unsafely.

The Makita blade guard has a tool-free manual lock that works smoothly through the operating range, even when it’s gunked up with slurry or dust. Next I like the Stihl’s friction pad. It works like a brake pad that’s always half on. It presses hard enough to hold the guard in place while you’re working, but not so hard that the guard isn’t easy to adjust. It’s a great feature that makes for foolproof guard placement. The Partner model has a friction pad, too, and adds detents, making for both foolproof and positive guard placement. The Multiquip’s friction lock knob must be un-screwed and re-tightened. It’s not difficult but requires more effort.

Balance. While all the product manuals caution users not to cut with these saws while holding them above shoulder height or while you’re on scaffolding or ladders, there are times when that’s exactly how you have to use them, and that makes balancing these tools “out of position” a big deal.

The Stihl is an exceptional, well-balanced, mobile tool. It’s the lightest saw and is easy to move into position and keep on the line, especially in a cut-out or demolition situation. The Stihl also is great for lugging over big rubble piles on large demo jobs. I like the Makita even more. It’s got terrific balance, and once it’s in position and cutting, it runs so smoothly I find it to be the most comfortable saw by far. Both the Multiquip and Partner maintain good balance out of position, too.

Blade Change

As an abrasive blade wears down, it cuts slower and forces the saw to work harder for less gain, so when you notice a significant decrease in cutting performance, change the blade. Also, don’t quickly re-enter your kerf after changing abrasive blades. The new blade is thicker than the old one and can bind, potentially causing the tool to jump unpredictably.

The wheel changes on each saw are straightforward, but the Multiquip has an ingenious feature: reversible blade collars that accommodate different arbor sizes.

Wet Sawing

Water. Cut-off saws are notorious for their dry-cutting dust clouds. Water attachments reduce the airborne dust to slurry like you would find in a tile saw tub. Eliminating the dust is nice, but don’t be misled?you’re trading dust clouds for a river of slurry. All the saws come equipped with plastic quick-connect hose couplers. They work, but not for long; we changed them out for tougher brass fittings.

The Right Blade. Don’t use composition blades for wet cutting. They’re porous and absorb water, which can compromise their structural integrity, causing them to fly apart while in use. Manufacturers suggest not even using composition blades that have been in storage for a year because they may have absorbed humidity. Any diamond blade can be used wet because they’re non-absorbent, but diamond blades labeled for wet-cutting perform better wet.

Maintenance & Service

Air Filter. When it’s time to clean the air filter I want a dry pre-filter that I can remove without tools, tap clean, and re-install. The careful cleaning is for the shop.

The Multiquip, Partner, and Stihl use oiled pre-filters. The Multiquip uses a thumbscrew to access it while the Partner requires a screwdriver. The Stihl filter access is tool-less and works well. Makita’s pre-filter is top-notch. While all the manufacturers recommend cleaning pre-filters with soapy water, Makita’s is the only dry pre-filter with tool-less access; a quick tap on a clean surface has me back to the races in nothing flat.

Spark Plugs. You have to change spark plugs less often than pre-filters, but easy access is still good. Makita earns top marks: The same tool-less pre-filter shroud gives you spark plug access. The Stihl spark plug change is tool-free and works nicely. Both the Multiquip and Partner require a screwdriver.

Belt Tension. Improper belt tension can lead to accelerated wear on shafts, bearings, and the belt itself while robbing the tool of power. Stihl’s automatic belt adjustment is impossible to screw up: Loosen three nuts and spring tension takes over. The Makita and Partner use an indexed adjusting screw and two bolts, similar to a chain saw, which work fine. The Multiquip uses a wrench-operated cam that also worked well.

Fueling. The Stihl is the only saw you can refuel when it’s standing upright. I like this, combined with the large, easy-to-grasp fuel cap. The Makita also has a large, well-designed fuel cap with a tool slot in case the cap gets too tight; it would be better if you could refuel it upright. The Multiquip and Partner fuel caps are similar. They’re a little smaller and don’t thread as smoothly as the others.

Big Guns

These saws are the big guns of residential construction. The Makita takes high marks for its great power, balance, and controls. It cuts powerfully in and out of position and devours tough materials. The Stihl ranks a close second. It’s beautifully balanced with outstanding controls and easy maintenance features. Third comes the Multiquip. Its power, balance, and vibration are satisfactory for most applications. Partner is next with a good guard, power, and fine balance.

David R. Crosby is a custom builder in Santa Fe, N.M., and frequent contributor to Hanley-Wood’s TOOLS OF THE TRADE.

Thanks to Hilti for supplying the diamond and abrasive blades for this test.