By Tim Uhler
Last fall I reviewed several saws that collect the dust generated when fiber cement is cut. More recently, I tried out a new contender in this category: Ridgid's R3400. Unlike other dust-collecting saws, this machine doesn't rely on a vac. Instead, it contains a fan that pulls dust out of the blade housing and sends it through an 8-foot hose into a covered drywall bucket. It's a very clever design.
Blade Diameter: 5 inches
Cutting depth at 90 degrees: 1 3/16 inches
Cutting depth at 45 degrees: 1 1/16 inches
Motor: 8 amps
No-load speed: 9,250 rpm
Weight: 7.4 pounds
Cord length: 11 feet
Street price: $199 (includes saw, blade, hose, filter, and filter clamp)
It's also very efficient. Only a small amount of dust escapes from the cut and almost none from the filter. Working without a vac is great because you have one less tool to haul around and supply power to. Also, the collection bucket is smaller and lighter than a vac — you can tuck it under the worktable and, when you're working off staging, hang it out of the way. At the end of the day you can empty the bucket and store the filter, clamp, saw, and hose inside.
According to Ridgid, you should clean the filter after every 100 cuts by taking it off the bucket and sucking the dust out of it with a HEPA vac. We made at least that many cuts without clogging the filter — though we did notice a decrease in collection efficiency. We cleaned the filter by shaking it into the dumpster. The R3400 fiber-cement saw collects dust very efficiently. A fan in the back of the tool pulls dust out of the blade housing and feeds it through a hose to a fabric filter attached to the top of a drywall bucket. The exhaust air escapes through the filter and the dust passes into the bucket.
I liked using the R3400 because it's small and light. While the 7 1/4-inch models I tested last year weighed at least 11 pounds apiece, this 5-inch saw weighs only 7.4 pounds.
However, there is a downside to the smaller blade. Whenever possible, our crew gang-cuts siding. A 7 1/4-inch saw will cut through seven pieces of HardiePlank lap siding and go deep enough into the eighth that I can snap it off by hand. The R3400, by contrast, will only go through three full pieces and deep enough into the fourth to snap it off.
Still, for me it's a reasonable trade-off: I'm willing to sacrifice some cutting capacity in order to use a lighter tool and avoid the hassle of hauling around a vac.
Fixed depth-of-cut. The R3400's base can be tilted up to 45 degrees, but oddly enough it can't be adjusted up or down. This fixed depth-of-cut means you can't cut single pieces without the blade going deep into the cut table.The saw takes a 5-inch blade and has a fixed depth-of-cut of 13/16 inches. Here it's being used to gang-cut HardiePlank lap siding.
To keep from destroying the table during cross-cuts, I elevate the stock on a series of blocks. If I need to rip a single piece, I position the cut line so that the blade comes through off the edge of the blocks or table.
The saw comes with a six-tooth fiber-cement blade and cuts single pieces of siding like butter. But to gang-cut, you have to slow down a little. The view to the blade is unobstructed, making it easy to see your cut line. I normally use a wormdrive, so it took me about a day to get used to the blade-right configuration of this machine.
Using the R3400 is a little less noisy than using the models that require vacuums. It's not that the R3400 is quieter (it's not), but tool-activated vacs run on for several seconds after the saw switches off. At the end of the day, the carpenter removes and cleans the filter (left), empties the bucket, and stores the filter, clamp, hose, and saw inside (right).
The Bottom Line
After using the R3400 for a couple of months, I've decided it's close to being the perfect tool for cutting fiber-cement siding. It's light, does a good job collecting dust, and has an unobstructed view to the cut line. The only thing keeping me from saying outright that it's the ultimate dust-collection system for cutting fiber cement is that the depth-of-cut can't be adjusted.
Tim Uhler is a lead framer for Pioneer Builders in Port Orchard, Wash., and a JLC contributing editor.
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