Prepare for a major change in portable table saws. During the last few years, tool manufacturers have banded together to produce a new guard system for these saws, and Bosch is the first company to market it, on its new 4100 series saws. Trust me, this new system will change how we work.
Carpenters usually remove their saw guard units and even throw them out. They can't use the splitter for rabbet cuts, the guard for narrow rips, or the pawls for cutting pre-finished material, but since these components are part of one assembly, the whole thing must be removed. The plastic guards easily become scratched and impossible to see through, and on top of that, most saw guards are difficult to remove and re-install. The new Smart Guard system promises to change all that with its modular components that can be attached or removed independently, and without any tools. This change is good, because safety and craftsmanship go hand in hand, and it will also please insurance companies, OSHA, and attorneys. A large percentage of jobsite accidents occur on table saws, and most of those could be prevented by using a guard system.
The Splitter. The heart of the system is the splitter, which keeps the kerf from closing and pinching the rear teeth of the saw blade. In the past, it's been a major headache to install the splitter, let alone adjust its alignment so it doesn't bind during cutting. Bosch solves that problem with a single lever that secures the splitter to the saw and locks it in alignment every time.
Out of the box, the splitter on my saw was slightly loose after locking the lever in place, so I had to remove the splitter assembly and tighten the nut on the rear of the lever bolt to fix the problem.
Aligning the splitter with the fence is an easy but critical adjustment. Following the detailed instructions in the manual, I set the splitter both parallel to the fence and centered behind the blade. Once the splitter is aligned perfectly, you can put away all your wrenches. This system is completely toolfree.
The Riving Knife. With the guard and pawls removed, the splitter can be lowered to work as a riving knife, which is simply a splitter held just below the height of the blade. In this position, the splitter provides kickback protection when making non-through cuts. When using a blade smaller than 10-inches in diameter, such as a dado set, the riving knife is too tall and must be lowered all the way beneath the saw table.
The Blade Guards.
The only similarity between the new Bosch system and conventional guard units is that the splitter supports the blade guards and the pawls. Another toolfree lever latches the Bosch guard assembly onto the splitter, so attaching and removing it is literally a snap. The assembly is made up of three main pieces. The upper aluminum guard is open down the middle, like a tuning fork, and allows an unobstructed view of the blade. The two-piece plastic side guards hinge independently on either side of the blade. You can flip up either guard into a locked position and slide the rip fence right up to the blade for narrow cuts.
Because the top guard is open and the side guards are perforated, dust collection is not enhanced much by the guards, but the Bosch saw generally does a good job of dust collection.
The Pawls. I've never been fond of anti-kickback pawls. Most of them scratch pre-finished material, and they always interfere with narrow rip cuts. But when making repetitive rips on hardwoods, they add some real "teeth" to the level of safety. Fortunately, the pawls are easily removable; just squeeze their locking pin and lift them off.
Digital Fence. Bosch's new digital fence is also revolutionary. The display can be set for increments of 1/16-, 1/32-, or 0.01-inch, or for 0.5-mm. I've always measured in 32nds as "strong" or "weak" 16ths–you know, "11/16 strong"–but using this readout requires learning the actual fractions themselves. Unlike laser guides on miter saws, I think digital displays are here to stay. When not in use, the digital display docks magnetically to the left side of the fence rail, out of the way. When you're ready to use it, slide it up against the rip fence and a magnet latches it in place. Then zero out the fence next to the blade, press the reset button on the display, and you're good to go. The display shuts off automatically after a short time of inactivity but remembers its location as long as it remains attached to the fence.
Onboard Storage. Another reason blade guards are seen once and never again is that there's never been a convenient place to store them. Bosch solves that: both the guard and the pawls clip onto a holder beneath the saw, and they won't vibrate loose. I knocked over my saw, and the only thing that fell off was the throat guard.
Gravity Rise Stand. I've never used a table saw stand with wheels before. I've always felt they were too bulky to store in my van, too heavy to lift and carry, and too difficult to wheel around on a jobsite. But I really like this new stand. It's easy to roll around, and set-up is a one-man breeze. Folding up the stand only takes a second and almost no energy, so moving the saw is a pleasure.
By now, you can guess that I think Bosch's new features function well and will improve user safety and accuracy. As for the saw itself, the Bosch is still the smoothest cutting, quietest, most accurate jobsite table saw I've ever used.
–Gary Katz is a finish carpenter and writer in Reseda, Calif., and a member of Hanley Wood's JLC Live construction demonstration team.