Table-Saw Technology Aims to Save Fingers

TomW · Dec 25, 2004

Ever heard of the movie "Gone in 60 Seconds?" Well guess what - it doesn't take that long. I have been a woodworker for over 30 yeas. I have been so safety conscious, I don’t even have a radio on. However, two weeks ago yesterday –I had just pushed the
48” 2x4 I was ripping through the saw and was and was pulling my hand back to shut the saw off and glanced down to see the switch when it happened. I thought what flew past my head was a piece of wood – never expecting it to be the end of my thumb! For the last 2 weeks, the biggest thing I have had to deal with is the disappointment I have had in myself – Mr. Safety! I know how dangerous everything in my shop is – but guess what – it can happen to you! I know, it happened to me. Would this saw have prevented this accident? I believe it would have in two ways – 1) the anti-kickback plate in the may have redirected my hand away from the blade, and 2) I believe the blade would have stopped and dropped. (Where have we heard that phrase before?). My $125 NEW blade would have been trashed, but I would not have had to kick in my $500 deductible on my insurance – like you can put a price on having my thumb re-designed! I have one on order – and can’t wait for it to come in. How many of you have paid thousands of dollars on insurance you may (hopefully) never use? I have and will continue to do so.
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BrettW · Dec 26, 2004

sorry you got hurt,
so it happened because of a kickback on the board you were ripping? Pulled you hand back into the blade?
never considered that but it makes perfect sense. You certainly can't get your hand off a board as fast as the saw can grab it and send it backwards.
best of luck with the new saw and the recovery,'
please keep this thread open and let us know what the manual says about cutting metal/ wet wood or any other limitation on the saw,
brett w

dixiedrifter · Dec 27, 2004

I'm not surprised what an electrical sensor can do nowadays.

I used to work at a prison, and they had a heartbeat detector they put on trucks to detect escapee's before they could escape inside the back of a truck.

Well one day, we hooked it up to a truck that had a partial load remaining and the alarm went off.

We got inside and looked around the cab and sleeper, then proceeded to search the trailer, and still could not find anything or anyone in the truck and the alarm was still going off.

Well, during the time one of the guards was in the truck searching, another guard happened to notice a mouse running out the back door.

Sure enough, as soon as the perplexed guard exited the rear of the trailer the alarm went off.

markct · Dec 27, 2004

so how did this so called heartbeat detector not detect the drivers heartbeat? sounds more like it was simply a motion detector or heat sensor

TomW · Dec 27, 2004

Bret - No - the board did not kickback at all. It went through the saw just fine. I mentioned the kickback plate because I think if I had one, my hand might have been pushed away from the blade. I think that would be another benefit of HAVING a kickback plate. This happened after I pushed the board completely through the saw and was bringing my hand back to turn off the saw. I think I had my hand too low - too close to the blade. My saw is an older Sears - before the days of these antikickback bars. I think that would have saved my thumb!

Thanks for the encouragement - from the email from SawStop, I should have the saw by the end of Q1, 2005. Over the holidays, I spent some time on the website of the company they indicated would be making the saws for them - very impressive unit - even without the sawstop. I would like to see the demonstration live; however, since that probably won't be possible, I am looking forward to the arrival date.

I think there may be more concern with metal than wet wood simply because metal will conduct a current, where wet wood will not. This system apparently works on the transmittal of "human electricity" rather than moisture. However, the hot dog must have conduced the current, too. This could be very interesting. Why one would, but another one would not. I will keep you in the loop.

GregJ · Dec 27, 2004

I have been watching this thread with interest. I am thinking about upgrading my table saw and this technology is very interesting. I came across a good woodworkers forum that might be of interest. In fact this is a link to a guy who has received one of the first SawStop cabinet saws. MillCreek Forum . Thought I'd share. I hope if anybody sees one "live", they'll report back. I'm interested in the contractor's saw.

Greg

markct · Dec 27, 2004

( I think there may be more concern with metal than wet wood simply because metal will conduct a current, where wet wood will not. )

wet wood sure will conduct electricity, not as much as metal, but enough to trip it may be possible, think about it, they demonstrated it with a hotdog, that doesnt conduct as much electricity as metal, but still conducts a slight amount which is enough. i have a feeling that word of false triggering on these saws will be going around in not too long, give it time

TomW · Dec 27, 2004

I just sent Renee (from the SawStop company) an email asking about how the system differenciates from human vs. non-human - such as wet wood, metal, etc. I also asked about what would need to be replaced and at what cost once the mechaism has been activated to stop the saw. I will keep you all updated on her responses.

TomW · Dec 27, 2004

UPDATE - Here is a reply to my questions about wet wood, curring metal, and what needs to be replaced...

Certainly cutting metal will trip the system unless you engage the bypass which is there for just that reason. Wet wood doesn’t conduct electricity nearly as well as a human – largely because it isn’t salty like blood. Therefore, only the very wettest wood could create any potential issue of a false trip. In addition, the system tracks the effect of wet wood and if it reaches a level where it could be difficult to distinguish from human contact it shuts the saw off and flashes a code to indicate that you will need to engage to bypass to finish the cut. Keep in mind, the type of wood we are talking about here is spraying a mist of water when you cut it and dripping wet, so it would very, very ever be cut on a tablesaw.

If the system is ever triggered, you need to replace the brake cartridge ($59) and, in most cases, the blade. This just takes a few minutes to complete.

markct · Dec 27, 2004

( flashes a code to indicate that you will need to engage to bypass to finish the cut )

thats the last thing i want, another tool with electronics to go bad and cost more than the saw to replace in ten years, my father has a rockwell saw he bought used about 35 years ago, it still works great and if anything breaks it could be easily made or obtained, thats not usualy the case with anything electronic, usualy in ten years its obsolete, for example at work we have a cnc miller thats basicly like a bridgeport mill, it was made in the early 80s, when we needed parts we were told not a single part was available for the machine, so it took a good deal of work to fix with other substituted parts, alot of downtime and cost, wheres the bridgeport manual milling machine sitting next to it that is twice as old i could get almost any part for it in a matter of a few phone calls. and i know that after the second time i forgot to turn off the safety to cut aluminum and destroyed a 59 dollae stop block and 30 or 40 dollar blade you can be that thing would be left off and unused, its a neat concept but in reality i just dont think its practical except maybe in a production environment where you are always cutting dry wood only