Tool Review: 6 Concrete and Masonry Cutting Systems
A review of six concrete cutting tools that help answer the OSHA Silica Standard rule requirements
By Michael Springer
By now, anyone who cuts or drills into concrete or masonry knows that the new Occupational Safety and Health Administration (OSHA) standard has changed the way this work must be done. OSHA’s silica standard aims to limit worker exposure to respirable crystalline silica, which is known to cause silicosis, lung cancer, chronic obstructive pulmonary disease, and kidney disease.
OSHA standard 1926.1153 applies to all work during which employee exposure may be at or above the action level of 25 micrograms per cubic meter of air (25 μg/m3 ), averaged over an eight-hour day.
An employer can choose to take responsibility for assessing the exposure of each employee by sampling and analyzing the air quality at a worker’s area and/or by providing objective data to prove the work methods keep the silica dust below the permissible exposure limit (PEL) of 50 μg/m3, averaged over an eight-hour workday. Or, an employer can choose to follow specified exposure control methods detailed within the OSHA standard in a document called Table 1, which can be viewed at osha.gov/silica/Table1sect1926.1153.pdf. You also can read more about your responsibilities if you employ workers at osha.gov/Publications/OSHA3681.pdf.
I used handheld concrete cutting tool systems from six major brands: five grinder-type cutters designed for dry use only, and one saw made to be used either wet or dry.
The four small grinders cut to a maximum depth of about 1 inch for thin CMUs and expansion joints in concrete. These are more difficult to hold perpendicular to a slab than larger cutters, but their freehand abilities make them the go-to tools for crack chasing, concrete repair, and tuckpointing. The large grinder-type cutter reached deep enough to cut through residential slabs nearly 5 inches thick, and the lone saw in the test worked well for cutting straight lines up to 2 inches deep.
Bosch – GWS13-50VS grinder with GA50DC shroud and VAC090A vac
Specs: 5-inch grinder, 13 amp, variable speed up to 11,500 rpm, lock-on slider switch, electronic clutch. Shroud shoe raised up on wheels, multiple depth stop settings (in metric units), and nice angled vac port. 9-gallon wet/dry vac, 150 cfm, switched automatic filter cleaning mechanism, 9.5 amps, variable speed, tool-activated outlet, comes with single 99 percent or better filter, HEPA filter available.
Pros: Filter cleaning feature of vac can be turned off for improved dust collection
Cons: Wheeled shoe provides a gap for dust to escape
DeWalt – DWE46103 cutting tool with shroud and DWV012 vac
Specs: 5- or 6-inch grinder, 13 amp, 9,000 rpm, lock-on slider switch, electronic clutch, soft-start. Shroud has mostly open design, pivoting foot for setting depth, all steel construction. 10-gallon wet/dry vac, 155 cfm, full-time automatic filter cleaning mechanism, 11.6 amps, variable speed, tool-activated outlet, comes with dual HEPA filters.
Pros: Door on shroud can be hinged open for closer access to corners; open-sided design allows very good visibility of cut; steel shroud sturdier than other designs
Cons: Open shroud lets a lot of dust escape at times and seems to be made for tuckpointing only and not cutting; lack of a shoe makes it difficult to hold tool perpendicular to work surface; lack of a sight on front of the shroud makes it difficult to cut along a marked line; filter cleaning feature of vac can’t be turned off to improve dust collection
Hilti – DCH300 cutting tool with 212131 shroud and VC300-17X vac
Specs: 12-inch cutter with large grinder motor, 20 amp, 4,900 rpm, non-locking trigger switch, soft-start. Shroud fully enclosed and shoe sits tight against cutting surface, spring-loaded shroud can plunge cut down to depth stop setting up to 4 3/4 inches. 17-gallon wet/dry vac, 314 cfm, switched automatic filter cleaning mechanism, 17.5 amps, water drain hose, comes with single 99 percent or better filter, HEPA filter available.
Pros: Deepest cutting, handles slab and cut-off work others can’t; filter cleaning feature of vac can be turned off for improved dust collection; retractable shroud provides good dust collection, even when plunge cutting
Cons: Heavy machines—cutting tool over 20 pounds and vac over 60 pounds (when empty)
Makita – GA5040X1 grinder with shroud and XCV04Z and VC4710 vacs
Specs: 5-inch grinder, 10 amp, 11,000 rpm, lock-on slider switch, internal suspension to reduce vibration. Shroud fully enclosed, large shoe sits tight against cutting surface, spring-loaded shroud can plunge cut to a depth stop, grinder handle attaches to shroud for better balance. (XCV04) 2.1-gallon dry vac, 127 cfm, automatic filter cleaning mechanism (cycles once when turned on or off), 9.2 amps, variable speed, comes with single 99 percent or better filter, HEPA filter available. (VC7410) 12-gallon wet/dry vac, 135 cfm, full-time automatic filter cleaning mechanism, 12 amps, variable speed, tool-activated outlet, comes with dual 99 percent or better filters, HEPA filters available.
Pros: Grinder felt stronger than the others when slowed by stones in the concrete and extra force had to be applied; side handle attachment point on the shroud aids the ergonomics of pushing or pulling the tool forward; small XCV04 vac can be run on two 18-volt battery packs for greater portability for cleanup uses (must be plugged in to achieve airflow required when connected to grinder though)
Cons: Grinder is the only one without a safety switch – if plugged in with the switch locked on, the tool will start; shroud leaves a thin line of dust to the right of the shoe that requires extra cleanup after cutting; filter cleaning feature of VC7410 vac can’t be turned off to improve dust collection. Small capacity of XCV04 vac requires more frequent emptying, and the lack of enclosed filter bags makes this a messy job as the loose filter has to be lifted out of the dust packed around it in the open canister, creating more worker exposure to dust than other vacs
Milwaukee – 2780-22 grinder with 49-40-6110 shroud and 8960-20 vac
Specs: 4 1/2- or 5-inch grinder, 18-volt cordless, brushless motor, 8,500 rpm, non-locking paddle switch, filter screens for motor vent. Shroud with closed shoe design, pivoting shoe for setting depth. 8-gallon wet/dry vac, 148 cfm, switched automatic filter cleaning mechanism, 7.4 amps, variable speed, tool-activated outlet, comes with dual filters, final stage is HEPA.
Pros: Very good dust collection overall. Cordless grinder offers a little more portability, but is still tethered to a hose; filter cleaning feature of vac can be turned off for improved dust collection
Cons: Cordless tool had weaker sustained cutting abilities than corded tools, making 1-inch deep cuts less than 10 feet long on a battery charge, and usually overheating the battery pack at the halfway point; swapping the grinder out for one of the brand’s corded models would be much more productive for prolonged cutting, especially one with a lock-on switch instead of a paddle switch that must always be squeezed
Skilsaw – SPT79 Medusaw
Specs: 7-inch worm-drive circular saw, 15 amp, 5,100 rpm, non-locking trigger switch. Shroud is upper wheel guard, shoe raised up on wheels, spring-loaded mechanism lets saw plunge cut down to depth stop setting up to 2 inches. Vac port vented through the front handle for dry sawing, supplied water hose attachment for wet cutting.
Pros: This saw cut much faster and easier wet than dry, with less vibration and excellent dust control; tracks very straight in cuts, and four sighting points located on the saw are helpful for following a line
Cons: Dry use of saws not covered in Table 1 so alternative exposure control methods would have to be followed to saw dry; dry cutting according to the manufacturer’s instructions and with the saw attached to a compliant vac is slow and lets a lot of dust get by; play in the spring-loaded depth stop catch causes extra vibration during cutting sometimes which requires excessive downward pressure on the rear handle to stop, which is uncomfortable.
Michael Springer is a tool tester and tool industry journalist in Boulder County, Colo.