Saturday, October 15, 2011
Last year the school where I teach replaced an older Delta contractor's model saw with the nice table saw shown above. It is a SawStop brand table saw. Before we go any further with this post, I wish to mention that I have no financial interest with anything to do with this product. We chose the SawStop saw for several reasons. First, it was a high-quality product and was we felt it was a good value. Second, it's price was very competitive with similar saws in it's class for size and power. Third, it has the SawStop's patented safety feature.
What is this special feature?
It has a safety device built inside that detects conductivity through the blade. If something conductive - metal, wet wood, or the operator - is detected, the SawStop's safety device engages. If you do actually wish to use the saw to cut something conductive, you can determine if what you are going to cut is conductive (before making the cut) and you can dis-able the safety feature if you so desire to make the cut. (With a key - using instructions provided in the manual.) When the safety device engages, a perforated aluminum shoe which is part of an expendable cartridge is pushed up into the bottom of the spinning blade by a spring, stopping the blade's rotation and causing the arbor assembly to drop the blade below the surface of the table. This takes place in literally thousandths of a second. Check out the time lapse video below:
We've had the saw for over a year now and it has been used without incident by students with a wide variety of experience. Until last Wednesday.
I received a call at about 8:30 in the evening on Wednesday from a fellow instructor to let me know that there had been an incident in his class and that the SawStop safety feature engaged. A student was making a cross-cut on the saw using the miter gage. We're not entirely certain of what happened, but we suspect that the piece of stock that she was cutting was a bit short and not well supported by the miter gage - it should have been backed up with a longer piece of sacrificial stock screwed to the miter gage. At any rate, we believe that the stock pivoted around the corner of the miter gage causing the piece to jam and kick back, taking the piece the student was cutting and her hand into the rotating blade.
A loud "BANG!" was heard by the class (...and likely everyone else in the building!) and the stunned student was standing at the saw trying to figure out what had just happened. The piece the student was cutting was damaged and a small nick was in one fingernail - no blood was drawn. The saw had performed as advertised and likely saved this student a serious injury. The student was shaken, but unhurt and (wisely) chose to head home for the rest of the evening. The cartridge and blade were changed on the saw and after some refresher information about safety in the shop from the instructor, the class continued.
We are all very pleased and relieved that this student was saved from what could have been a debilitating and life-altering injury. Plain and simple.
There is apparently legislation being introduced by the Federal Trade Commission (FTC) to require a device which functions similarly to the SawStop on all table saws. I think the time has come.
There has been quite a bit of discussion by both amateurs and professionals of late about these saws that was spurred by a lawsuit that was filed against Ryobi (I'm not picking on Ryobi - I'm sure there are other lawsuits against other manufacturers, but this one has been quite prominent in the news.) People who are complaining about the judgement and the FTC requirement say that they are concerned that these safety devices will make people complacent about proper, safe use of these saws. I've not found that to be the case, personally - when the blade spins up, it's still a 'gut-check' for me. Students that I've watched working with these saws still treat them with the respect that they deserve.
I strongly urge you to go look at this previous post. Everything in this post bears repeating and there are probably things that should be added, too. There is an image in the post which is a bit difficult to look at, but I think it is a good reminder of why you need to be safe in your shop and why these safety features on table saws are important.