Source: TOOLS OF THE TRADE Magazine
Publication date: April 14, 2011
There was no way for us to determine the long-term durability of the motors and gears in these saws. In my experience, those parts of an inline saw almost never wear out or break. When I've had to replace inline saws in the past, it was because parts on the outside were damaged beyond repair.
Other than the slide arm on the depth-setting mechanism, the most frequently damaged component of the saw is the base plate, which may bend if the tool falls. The best base plates are thick and heavily ribbed, like the ones on the Bosch, the DeWalt, the Makita, and the Milwaukee. The worst base plates are flat or nearly flat, like the ones on the Craftsman and the Ridgid. Skil's plate, with its rolled edges, falls somewhere in between.
All of the saws can be used with an optional rip guide. In most cases, this is the same scrawny guide carpenters used 20 years back – essentially a bar that connects a 3- to 5-inch fence to the base. It works okay, but I don't know anyone who uses it on a regular basis. The device is really more of a gauge than a guide; if you push too hard on the saw it will pivot off the fence and the rip won't be straight.
DeWalt developed a rip guide (DWS5100) that I actually like using. The fence, which will make up to a 14-1/2-inch rip, is about 19 inches long and connects to the saw with a pair of arms. It's big enough that you can push the saw hard and cut quickly and still produce a very accurate rip. This is a fantastic accessory.
Nearly all of these saws are well-made and functional, but as someone who frames for a living I liked the DeWalt best. It's powerful and rugged, and it has well-thought-out features, including an optional rip guide that actually works.
My second choice – despite its somewhat weak base plate – is the Ridgid. This saw is smooth-running, powerful, and equipped with a very nice guard. My third choice is the Skil. Compared with other models, it seems stripped down, but its upgraded guard and venerable reputation make it hard not to like.
Tim Uhler is a lead framer for Pioneer Builders in Port Orchard, Wash., and a Tools of the Trade contributing editor.
Worm versus Hypoid
Inline saws produce more torque than sidewinders because the gears spin their blades about 1,000 rpm slower. Bosch, DeWalt, Milwaukee, Ridgid, and Skil use worm gears; Makita and Craftsman use hypoid gears – as did an earlier model (DW378G) from DeWalt.
You can tell at a glance what kind of gears a saw has. The gears in both types of saw are bathed in oil, but in a wormdrive, there's a plug in the housing for changing the oil. There is no such plug on a hypoid saw; the lubricant is permanently sealed within the gear housing.
These design differences are due to the way worm and hypoid gears operate. A worm gear slides against the adjoining gear while a hypoid gear has more of a rolling action. Sliding is inherently less efficient than rolling and produces more friction and heat. Under sustained heavy use, the gear housing of a wormdrive saw can become hot enough to degrade the oil – hence the need to be able to change it. To reduce the amount of friction, the steel worm gear mates with a gear made from bronze, which has a lower coefficient of friction. Bronze isn't tough enough to use in every kind of gear, but it works fine in a wormdrive saw.
If you talk to tool manufacturers, you'll get conflicting reports about which type of gear is better. The companies that make wormdrive saws claim worm gearing is more robust and that their competitors use hypoid gearing because it's less expensive to manufacture. The makers of hypoid saws say that hypoid gearing has tighter tolerances than worm gearing and is more durable and more efficient at transferring power.
– David Frane