|Building a safer saw|
|Responding to the problem|
|Other paths to safety|
|So what's new?|
|The final responsibility|
"We have to make it very easy to make a non-through cut," said Scott Box, vice president of Steel City Tool Works. This new company designed the guard on their saws to be more accessible from the beginning. "All you have to do is loosen a wing nut on the back, and you can flip the guard up and out of the way. When you put it back in, it registers in the same position again and it's very rigid. That's the kind of thing we have to do as manufacturers, and make it user-friendly to the point that it doesn't become a pain to take off and get back on. You can readily go back to using that guard again as you change your setups."
For Bosch, Feldner noted that the guard on the company's new model 4100 job-site table saw addresses both vision difficulties and ease-of-use.
"Our whole goal in this design is to eliminate the two issues and give people a reason to actually want to keep it on," he said. "The blade guard is a split-guard design, using a top fork and two side barrier guards that prevent you from touching the blade. The fork design means that there are two prongs, so there's nothing that blocks your line of sight of where the wood touches the blade. The barrier guards can be locked in the upward position if you need to make adjustments on the blade, so you don't have to take the guard off to make accurate adjustments."
The main purpose of guarding is to keep hands from coming into contact with blades, but that covers only one of the table saw's two main dangers. While the guard itself may help to deflect a sudden kickback â€” the other main danger â€” their design doesn't prevent kickback from happening. For that, you need to keep the wood on the waste side of the cut from coming into contact with the blade.
Splitters, common on table saws for decades, help prevent kickback. However, because splitters attach rigidly in place to the saw their height is constant, usually several inches above the table. For that reason they can't be used for non-through cuts like dados and rabbets, and must be removed. European saws, however, have had a workable solution for that for a long time.
Riving knives, like splitters, mount behind the blade and prevent offcuts from drifting into the back of the blade. However, riving knives don't extend above the blade. In fact, they raise and fall with blade changes, always remaining just below the crest of the blade and making non-through cuts possible. U.S. manufacturers are now recognizing their value.
"We're incorporating riving knives with detachable blade guards into all of our newer saws," said Grizzly Industrial's Bill Crofutt. In addition, Grizzly's system gives the user more than one option on the knife. "Depending on the saw, some of the guards are attached directly to the riving knife. On others, the guard can be removed from the splitter, and leave that in place; and then the splitter can be removed and a riving knife dropped in. So, there are a couple different ways we're approaching it."
If riving knives are such a good idea â€” and if European use is any indication, they are â€” why are they only now coming to U.S. manufacturers' offerings?
"The only reason riving knives are here is because of SawStop," said Steve Gass, president of SawStop. "Manufacturers did that in response to the pressure that SawStop was putting on them â€” and by that I don't mean us directly calling and bugging them, but the existence of that technology pressured them to do something to address safety. In large part the developments that have happened over the last couple of years with table saw safety and the riving knife standard were quite literally a direct result of the development of the SawStop technology."