But I've heard reports from 3rd-parties that Altendorf's camera detection method is unreliable/glitchy and doesn't work as well as Felder's system. Maybe Altendorf fixed the bugs.
Also, Altendorf's philosophy of using cameras & ML instead of inductive proximity reminds me of Tesla's philosophy using cameras instead of LIDAR (Waymo).
EDIT ADD: >I'm not sure how comparable these alternatives are when two of them are "request a quote" kind of pricing, and the Altendorf is $7000+
My comment was about "industrial saws" so they're definitely not realistic alternatives to buying a jobsite SawStop for homeowners. I added italics to the adjective "industrial" to clarify this.
I'm not sure how comparable these alternatives are when two of them are "request a quote" kind of pricing, and the Altendorf is $7000+, unless you're considering an entire cabinet. None of them will go on a job site with you, for example. I would love to test the Felder system though.
That depends on how they fail. If they trigger on false positives, that's money wasted on lost time and damaged equipment.
On the flip side, if they fail a real case, it may well be because they engendered a false sense of safety, a bit like a sharp knife being safer than a dull one.
Yeah, they aren't comparable in the least. These companies use it for market segmentation. You'll only get this on the ridiculously expensive table saws. Whereas a Sawstop cabinet saw (the industrial one!), still expensive for an American-style table saw, is a fraction of the price. In the case of Felder, 10% the price!
Totally agree, and wouldn't really comment on it except to say that the cheapest Sawstop is $1-3k even on blackfriday. That's not really in the same league as other jobsite saws that are $100-300.
Each one really is a ~10x step in cost above the other. Of course quality and safety/reliability are higher too, and I know which I'd buy. But, comparable only sort-of.
Sawstop is really only about 2-3x the price of an equivalent saw. It's not 10x more.
The 100/200 dollar table saws are not really comparable (at a basic spec level, they're just not the same thing - 8" blades, smaller table, no fence)
Most reasonable products you would actually buy for a jobsite are in the $500 range. The same Sawstop is 1500. The cheap no-stand versions are $300. The same Sawstop is 900. Pretty sure they're targeting 3x as the price.
> Also, Altendorf's philosophy of using cameras & ML instead of inductive proximity reminds me of Tesla's philosophy using cameras instead of LIDAR (Waymo).
Kind of seems like the opposite. I could be wrong, but in the case of the saw the cameras/AI are probably more expensive to develop and deploy than the inductive sensing. With the cars though, it's the cheaper option for sure.
I don’t see the point of a Sawstop-type system for an Altendorf-style panel saw. The whole point of that saw design is that your hands are nowhere near the blade!
Often times when a product has some patent-protected feature, the product itself is substandard, but I have not found that case with sawstop. It's one of my highest quality tools.
It would be nice if the mechanism wasn't so destructive. I accidentally had an aluminum fence just a fraction of a mm too close, and it touched the blade. I was using a dado stack, and it did a number on the carbide teeth of the blades. Good dado sets are not cheap, nor is the sawstop cartridge.
We had a saw with a mechanism that was non destructive and SawStop sued them out of the country (Bosch REAXX). It's why my feelings on SawStop are complicated, they say they're all about safety and willing to work with others but stomped out the only one that tried.
Bosch REAX used compressed air cylinders to drop the blade without damaging it. They got sued into oblivion by SawStop because SawStop was somehow granted a patent on the idea of stopping a blade quickly. As a side fact, the Bosch sensor electronics weren't done properly and could sometimes be affected by BlueTooth.
The whole "releasing our patent" is simply SawStop's way of trying to lock out the competition. All their competitors (including Bosch) have said that it will take several years before they could develop an alternative product leaving them in violation.
Finally, the regulation SawStop is trying to force doesn't even solve the injury problems for a few reasons.
The biggest is that CPSC does NOT affect commercial saws. As it turns out, hobbyists don't have as many injuries as you might think because they don't use their saws all the time and they have a very healthy respect for them (there are exceptions of course). Most serious injuries happen because the guy at the commercial shop has become too complacent and made a mistake after a long day at work. This ruling does nothing to change that situation.
You also can't fix stupid. If blade guards and riving knives are left on saws, the chances of injury are incredibly low, but people choose to remove one or both of these. They'll also turn off the safety features and do something they shouldn't. SawStop safety is over-represented because the people who spend the extra money for one are already predisposed to take safety seriously.
This leads to the price issue. Table saw prices will go up from $220 up to a minimum of $600 or more. This increases the risk of someone not having that much money and then turning their circular saw upside down making an incredibly dangerous table saw without a blade guard, riving knife, or even a parallel fence massively increasing the baseline risk for injury.
I love the idea of SawStop and I think it's an amazing safety device, but after reading the arguments on all sides, I think we should leave the current saws situation alone and instead simply require each saw manufacturer to offer at least one AIM model in their product lineup by 2032 or so (while maybe getting the courts to fix up the colossal screwups they made with the SawStop patents). This will give them time to develop alternatives and maybe drive down prices over time until it finally (hopefully) makes economic sense to only sell AIM devices.
I'm struggling to imagine a scenario where dadoing <1mm from the fence was a good idea in the first place. I'm assuming you're talking about a miter/crosscut fence but still...
I've stopped myself just in time from triggering my Sawstop while using an aluminum miter gauge.
The scenario is that the gauge was set with reasonable (1cm) clearance at one angle, and then I changed the angle without re-checking the clearance, and the back side of the fence swiveled into the blade path. Pythagorean fail.
Or, perhaps with GP comment, used a setup with reasonable clearance for a regular blade, and then put in a wider dado, which ate into the clearance.
I had a sacrificial fence (wood) on the aluminum fence to reduce blowout. I had the aluminum extend to near the blade to reduce the deflection of the whole thing. It was too close.
Really, I should have sacrificed a crosscut sled for dado usage, but it really chews them up.
+1, I've had mine for 5+ years and it is still genuinely a joy to use. I went with the "buy your last tool first" approach and splurged on a 5HP ICS and don't regret a single penny spent on it.
Mostly unrelated, but I don't think SawStop is releasing its patent anytime soon like the article states. That SawStop press release was the CEO saying they would do so if the CPSC rule was passed, but the rule wasn't voted on. And even then they were only releasing one of their hundreds of patents.
They've pretty explicitly been willing to release all of the relevant patents.
The truth is it was always a red herring for their competitors.
The major players all have systems that don't rely on these patents.
Lawsuit discovery showed all of them had developed their own technology that was fine, patent wise. But it would have eaten into their profit.
Personally, I have an altendorf handguard sliding table saw, which will stop as fast as the sawstop, but not destroy the blade.
That table saw looks very nice, but also $7,000? That's not the same market that people are talking about.
I'm not so sure if other companies have the ability at a sub $2000 price point! Bosch came out with their own system that they thought was different. The product was on shelves for a year and then SawStop successfully sued. If a major company like that is unable to do it even after their lawyers gave them the clearance, I'm a bit dubious it's that easy.
I think free access to use the patented tech is only a part of the answer to building such a mechanism, and definitely a good first step. Looks to me like the build quality would make an even larger difference to the success of the device. For example:
> The fuse wire is designed to be stable enough to resist stretching or thinning over time despite the intense repeated vibrations from the saw use, ensuring it doesn’t prematurely release the spring.
"Just" some bad QA and the wire releasing the mechanism breaks too early needlessly destroying the saw, or too late needlessly destroying the hand. A patent won't fix that for the manufacturer.
I agree on all of this. But the others had already done the r&d. Take a look at the documents in the Massachusetts table saw injury lawsuit, from 2006, an example.
I recall reading that the majority of their patents were expiring in the next few years and the one that they’ve offered to not enforce (rather than release) is the important one that doesn’t expire until the 2030s.
> Despite previous litigation against would-be imitators of their safety brake, SawStop has committed to dedicating its original patent to the public when these new regulations go into effect.
> why does it appears as if this isn't much of a thing outside of the US?
American hobby woodworkers all have huge two- or three-car garages giving them the room needed to store and use gigantic machines like table saws. Such large homes are unusual in Europe, and mostly owned by people who don't work with their hands.
European hobby woodworkers don't lose their fingers to table saws because they're using circular saws instead.
I suspect America also has a lot more woodworkers; many of their buildings have wood frames, wood siding, and bitumen-over-wood roofs.
Homes as large exist all over Europe. Get into the cities where most people live and apartments don't have enough space, but just outside there are plenty of people with large houses. (they often have tiny garages though which doesn't leave enough space for a saw like this) In the US people live in apartments without enough space for a table saw as well, but houses with large garages are common (apartments often have garages, but they are too small for these saws and usually lack power). In my experience apartments in Europe are bigger than in the US but I've haven't seen enough apartments in Europe to be confident in that.
They really aren't. My house is a 1250 sq ft 4 bedroom house. It gets comments from friends and family for being relatively large for a 4 br here, since the norm is 1000 sq ft for a 4 bedroom. Similar style houses in the US seem to be about 2000 sq ft from a property search.
In the US, a 1200 sq ft or smaller home would be a post ww2 "starter home", usually 2 or 3 bedroom. Homes of this size are pretty much not being built anymore, the average size of a new home in the US has been around 2500 sq ft for decades now. The median size of all existing homes in the US sits just north of 2000 sq ft.
Average is not a good measure - more people in the US live in larger single family houses than in Europe. However those in Europe who live in single family houses have about as much space.
At least one hand is operating a circular saw and there’s often a spring loaded guard that snaps into place when the saw isn’t sawing. I’m sure plenty of people hurt themselves with circular saws, but as more of a hands-on tool you are very aware when using it. It is not nearly as precise or easy to use with large jobs as a table saw, however.
On a circular saw, the hand in motion maneuvers the cutting tool. On a table saw, it pushes the thing being cut. Either saw's blade sometimes grabs the material and kicks it back. If your hand is on that material, it can also be sent in an unexpected direction.
(This is just one scenario. Both tools are capable of unwanted removal of body parts.)
Lot of replies here but none of them have really hit the mark. European table saws are fundamentally different than American table saws, where the entire section left of the blade slides forward. Culturally it seems Europeans believe this is "safer" than the American style and therefore they don't need the blade safety mechanism. Personally I think that's nonsense, and apparently so do some of the companies because they've developed their own mechanism that they only use on their priciest saws.
Woodworking YouTube has changed this a bit. Since American creators are so widespread, everyone has gotten exposed to SawStop and I know at least a couple years back people were trying to import American-style table saws instead of the local European-style because that's what YTers have. I don't know if it was regulatory or what that has prevented the former from being more available in Europe.
Interesting seems like the European version is essentially an integral sled? That does seem much safer and inherently keeps hands away from the blade when used properly so a saw stop mechanism might not actually add a huge amount of safety real safety but is still a nice final safety measure. A lot of US literature and videos I've seen are heavily suggests using a sled whenever practical.
Also dados are prohibited (more or less) in the EU. So yes, there are regulatory issues. And btw, I just cannot find a sawstop to buy here (at a human price)
Right, dados are one of the things that baffle a lot of European woodworkers, myself included. Not that they don't seem useful; just a little on the iffy side of safety.
I'm not sure if they still make it, but Festool and Sawstop are owned by the same parent company, Festool sells the TKS-80 saw in Europe that has the Sawstop tech.
> why does it appears as if this isn't much of a thing outside of the US?
Patents. SawStop does not sell outside the US/NA to my knowledge and they hold all the patents required.
In 2015 Bosch introduced a system that did essentially the same thing as SawStop, but with a slightly different mechanism. SawStop sued in the US and won against Bosch.
Since 2017 SawStop is part of Festool, which explains why their tech is slowly making their way into Festool products. For example, the TKS 80 has the SawStop functionality built in. But at an MSRP of ~2.500€ it’s not really a hobbyist machine.
Bosch REAXX has a significant advantage, that being it is non-destructive to the saw blade when it activates. All you have to do is press a reset button and you are back to work. Not having the option of buying this tech instead of SawStop's in the US was a net negative for consumers, IMO.
One reason could also be that the US woodworking culture treats a table saw as an essential tool (especially the basic table saw, without a sliding table), while elsewhere track saws are used more, it seems.
If you run commercial production, then you do need a table saw (but one with a sliding table!), but for hobby work you might as well spend some time for track saw setups and be much safer.
They're very different tools, and neither is inherently safe. You can absolutely have kickback-like issues with a track saw if you're not careful when making plunge cuts, for instance.
A track saw is more convenient and arguably safer when breaking down a huge piece of plywood. After that it's no table saw replacement. You can't easily do repeated cuts of identical stuff width, you can't work on small parts, you can't make most of the common jigs, you can't do dadoes or box joints, etc.
I regularly do repeated cuts of identical stuff width with my tracksaw, so I'm not sure why you'd think you can't easily do that.
About the only thing the tracksaw is not good for are long cuts of narrow stock. And yes, dadoes, but I do those with a router and arguably you should not even try to do them with a table saw, unless you are trying to hurt yourself.
Implying that because of the possibility of kickback a tracksaw is comparably dangerous to a track saw makes no sense.
I recently made a cutting board with many tiny pieces - 0.5" square, several hundred of them. With a table saw it's "run pieces through, rotate 90 degrees, run pieces through" - not fast but WAY faster than having to move the track saw every time, and that second cut is impossible with a track saw.
On a table saw I can do crosscuts. I barely ever use my miter saw (in favor of my crosscut sled on my table saw) unless I'm trying to keep the table saw fence positioned somewhere precise and need to make a crosscut in the middle of my workflow.
And speaking of the fence: The table saw is a precision instrument. The track saw is not. I set up my table saw fence once, eight years ago. I have never had to adjust it or look again. If I want something an inch thick I set the fence to an inch and make the cut and it is correct. I don't have to draw a line on my workpiece, measure, and make a mark. I don't need to measure the final piece with calipers to see if I got close enough to actually an inch. I can work quickly and efficiently.
Then there's bevels - am I going to buy a new rubber track guard for every different angle I want to cut, or am I just going to use my table saw and tilt the blade? If I want to be precise and always use a zero clearance insert, at least I can make those myself rather than having to buy rubber molding.
I own a fairly nice track saw (Festool TS55) and a pair of good-quality tracks for it. I own several expensive chunks of metal which profess to do things such as align the track at a 90 degree angle to my workpiece which I am unable to trust or even to get working consistently. I'm not talking "oh, this is 89.7 degrees", I'm talking "I can see with my eyes that's not square, guess I'll go get a combo square and a pencil".
I have owned devices such as the Kreg jig which aim to make it easier to do repeated rips with a circular or track saw and while if you don't own a table saw they're better than nothing, they're nowhere close to the precision, reliability, or ease of use of a table saw.
I love my track saw. I hate trying to pick up and manipulate 4x8' or 4x4' pieces of wood on the table saw and the track saw makes my life much easier - but that initial breaking down is all I ever use it for, because for every other task the table saw is dramatically better.
Table saws are very common in Europe in hobby circles as well. If you take woodworking in school you'll learn to use it along with other tools. Also, you usually build the sliding table and other jigs yourself using the tracks on every table saw. They're called T-tracks, there's a couple different common widths.
I have an older Delta table saw and recently decided to sell it because a miter saw + track saw + some other tools you need anyhow does nearly everything a table saw would do, but uses space way more efficiently.
My table saw is space efficient because I also use it (covered) as a table in the middle of my small shop, sometimes to support work I cut with a track saw. And I added a router table to the extension, which just disappears as part of the table. It's a space dense with utility.
Sawstop wasn't available for purchase in the EU until last month. The only version that was available was the very expensive Festool table saw, though they are both from the same company. I'm currently waiting on my compact Sawstop to be shipped from the first batch.
Table saws are less common in Europe for hobbyists, also things like dado blades are effectively banned, which means we actually use the blade guards that come with saws. We tend to use routers for a lot of the things Americans will use a table saw for.
I believe they just don't market them there, probably not interested in confirming to all the different regulations for different markets, etc. I know some folks have imported them, but I don't think they are sold directly. I think Laura Kampf claims to have one of the first SawStops in Europe.
Ironically, previous ones worked beautifully for me but this one fails on my desktop Firefox. Couldn't even select text on the page to copy paste, utter failure.
It's Ironic that this is basically an ad. Lumafield is an industrial CT scan provider, and these articles serve as an advertisement of their capabilities.
I think this is marketing done right. I am not in the CT scan industry, nor do I think I'll ever have the need for these services, yet I came out slightly more knowledgeable about the world around me after reading their article. Maybe one day I will have the need for commercial CT services, and Lumafield will be the first one to come to mind.
I bought my sawstop shortly after my partner started working in the medical field, where they'd see saw related injuries or amputations come in weekly.
Saw was expensive, yeah.. but they hold their value on the second hand market, if you ever even see them for sale.
I had a cabinet maker over last week, after he noticed my sawstop he showed me his 2 partially missing fingers.
The company also isn't playing games, the saw is beautiful and a lifetime purchase.
My shop teacher seemed to think the band saw was more dangerous than the table saw. Was he wrong, or is it just that table saws are used so much more than band saws that they dominate the injuries?
Table saws are dramatically more dangerous than band saws. When a band saw blade makes contact with whatever it's cutting, the force is in a single direction. Down at the table which provides material support. Table saws use a rotating blade and often a fence system. Lots of things can go wrong there, but it typically involves binding between the fence and the blade which can lead to kickback which can send chunks of wood through a wall or potentially more dangerous is it can cause the wood to twist violently into the blade risking bringing your hand towards the blade.
Here's a saw stop in action, so it's not gory. But look at how FAST things go wrong here and how violent the interaction was.
I haven’t used a bandsaw a lot, but I have seen some photos of gnarly lost fingers.
I use a table saw quite a bit and think there are more ways things can go wrong, most of which stem from kickback which happens in a split second. The wood will either fly back and hit you, or your hand will be pulled into the blade and you will likely lose a finger.
Both machines can be safe with the proper precautions. That said, I still enjoy my SawStop as insurance for my fingers since I still write software for my day job.
> I use a table saw quite a bit and think there are more ways things can go wrong, most of which stem from kickback which happens in a split second. The wood will either fly back and hit you, or your hand will be pulled into the blade and you will likely lose a finger.
One of the more horrifying things I've witnessed second-hand with kickback was a lucky third scenario. It was high school woodshop and one morning the teacher pulls us all over to the miter saw bench and points at a huge chunk that's missing from it. The bench surface was two or three layers of MDF glued and screwed together. He explained that someone had been cutting something on the table saw 8 feet away from it, had a kickback, the kickback missed but the piece of wood shot into the miter bench and that was the result. Thinking about what that same piece of wood would have done if it had hit a human... yeesh, I definitely treated kickback with a lot more respect after that day.
They can both be dangerous but one difference is that the band saw _seems_ much less dangerous and people would take it less seriously. In a shop full of adolescent novices I could see this causing more injuries whereas the tablesaw is probably more closely supervised and people will respect it more.
I'd say overall a tablesaw is more dangerous compared to a band saw because it has the additional failure mode of kickback which happens occasionally even to very experienced operators.
I think that's probably it. The band-saw didn't really look different or more intimidating than the jigsaws we had previously been using. The table-saw looks like it wants to kill you.
Ever seen someone bind the material in the table saw where the material kicks back into the operator? Here's just the first example from a quick search:
A basic consideration of the energy involved should tell you.
355mm radius disc, mass 1kg, moment of inertia is 1/2 mr², so 0.06 kg.m² [1]. This ignores all inertia of the arbor and motor rotor, mind, which is possibly significant (smaller radius but dense, depends on the transmission whether the motor is part of the blade system - if there's a clutch or belt to let go, then the motor isn't really part of the problem, but it's also not going to be part of the solution), Say it spins at 4000rpm, or 420 rad/s (some saws go to 6000 plus and this is quadratic).
So kinetic energy in the blade alone is 1/2Iw², or 0.5 * 0.06 * 420², or 5.2kJ. For comparison, a rifle bullet is about half that, which seems right ballpark on the face of it.
So to remove that energy in 5ms (SawStop's claim) is 1MW, or a current of 4000A at 240V, or 8000A at 120V. I don't know if any big saws run on that voltage in the US (may small ones?), but let's take the lower rest-of-world figure anyway. That's roughly 1300HP or 4 top-spec Tesla Model Y's at full throttle (320kW each).
This is not completely technically impossible to deliver - you need about 400 0.1 farad capacitors charged to 250V, which are 100mm in diameter and 250mm tall and around $150 each, so a fridge-sized box, maybe two[2]. Some very large and pricy solid state switches will be needed too, and some nice copper busbars to get the current where you need it. Actually pushing 4000A into a motor winding for 5ms isn't that easy either as it's a canonical example of an inductive load, so you need even more current, plus hopefully a way to stop the current when done before turning the inside of the motor into a plasma ball. Evaporating the motor winding before you've stopped the blade is no good, and it'll be nice to use the saw again, so you'll need to uprate the coils massively, which will make the motor very heavy, very large and very expensive.
There are probably other issues like induced voltages far higher than main voltage the will need management. As mentioned earlier, you will also not be able to use, say, a belt drive - the motor needs a very stiff physical connection to the blade.
So, you won't break physics to do this, but it will be large, heavy and incredibly expensive. $50k in caps alone.
Flipping the blade physically away from the obstacle is a much better bet. Which is actually SawStop's real trick - all that kinetic energy in the spinning blade system is grabbed and harvested to move those kilos of steel down and away in a few milliseconds. Stopping the blade is just a handy side effect of stealing all the energy. You could possibly do the same with an electrical system, but it would still be very large and very heavy compared to using the exact same huge kinetic battery that will always be there (or it's not a table saw) and which is actually the threat to safety in the first place.
It's actually quite interesting to see the relative weakness of electrical forces illustrated this way. Even quite prosaic mechanical objects can develop powers that require electrical systems the sizes of small rooms to rival. And again, chemical systems contain more power still: all that spinning mass is the energy contained in a few grams of gunpowder.
[1] Edit: I double counted a factor of 1/2 in the MoI - it's actually more then I first estimated!
[2] Another underestimate as you really need a lot more as you have to get that energy out fast and you can't wait for the slow tail of the discharge curve to finish. Plus at least Nichicon only seem to go to 160V for 0.1uF!
Full disclosure, I now think I badly messed up the capacitor energy calculation perhaps while recasting it from a battery system to a capacitor system. You probably don't need nearly that many just to store the energy usefully. But I estimate the other factors, like the discharge curves needing you to over build to get enough energy into the first 5ms, balance it out at to something vaguely fridge-sized anyway.
The start-up current of large table saws are truly massive. As in multiples of it's nominal "peak" operating current.
So to bring the blade to a complete standstill, in significantly less time than start-up, is probably not feasible, unless you have a massive bank of capacitors with stored energy so that you can dump all that current in the motor without burning your building's wiring. But that will probably vaporize the motor.
No, these motors usually have a very slow spin-up time (probably an induction or a DC brushed motor)
So even if you send peak current it won't (this is for the DC brushed, for the induction it can't be reversed unless you have a speed controller - also called an inverter)
Generally you want to oull the blade down, more than you want to stop it. Get it away from the finger, rather than stop it so a finger can push into it safely.
Not really related to the actual content of the post, but I use a Lumafield at work constantly and love it! The scan quality and software is amazing. Scanning electronics is so much fun, and so helpful!
There is a removable cartridge that stops the blade. It ruins the blade. The cartridge gets swapped out with a new one in a few minutes (the table top of the saw can be partially opened) and costs about $150 .
> When the brake is activated, the most recent data is stored into memory and SawStop can download the data from the activated cartridge. This data is very important to our continuing research and development program. If SawStop’s engineers verify the activation was due to contact with skin, you will receive a free replacement cartridge. If you are unsure why the cartridge activated, you can also ship the cartridge for analysis to SawStop’s service engineers. When the cartridge data is downloaded, we then can determine what specifically caused the brake to activate so that further unintended activations can be prevented. The brake cartridge evaluation is free of charge the shipping of the brake cartridge is paid for by the customer.
It _may_ destroy the blade. I've had mine for about 10 years, and have had two false triggers in that time (both times, dumb mistakes on my part). Neither time has the blade been destroyed.
I sometimes mill my own lumber from windfall on my property - in the first instance somehow I managed to put a single piece of near green lumber (~40% moisture) in the same rack as some lumber I knew was dry.
A few weeks later I needed some scrap for something, grabbed the piece closest on hand, pushed it into the blade and immediately triggered the wet wood alert and the blade spun down slowly. I knew that the wood wasn't wet, so started the saw up again and pushed it straight back into the blade only with more force, triggering it straight away.
Second time was due to cutting a lot of pitch heavy pine over an extended period of time - it built up on the cartridge and after a blade change that I didn't check the clearance on, it bridged the brake with the blade (i assume) and triggered on start up. (It comes with a tool to check this clearance after a blade change - I of course did not follow the instructions).
You can use wet wood or pressure treated lumber or even foil coated acrylic - but the key is that you need to be expecting this, and you put the saw in to by-pass mode.
At that point, it's just another dumb saw that will chop your finger off, but it won't trigger the cartridge, and you can make what ever cuts you need.
The way it tries to determine if it's wet wood / a body part is the capacitance change. Slightly different profile which they can use to make an educated guess (obviously erring on the side of caution).
This is why for some time they would give you a free cartridge if yours triggered on flesh - they wanted the data on there from real-life flesh contact to improve their calculations.
> This is why for some time they would give you a free cartridge if yours triggered on flesh - they wanted the data on there from real-life flesh contact to improve their calculations.
The automatic defibrillators manufacturers also will often send you a unit for free if you used your unit for an actual defibrillation. Same idea.
Ah, that explains why there is so much electronics in the cartridge! It seemed a bit like overkill, but returning the cartridge will get them their data.
You can manually disable the auto—trigger mode in those situations though (bypass mode).
It also doesn’t like anything conductive - so anything coated with Mylar, any kind of conductive dust or debris, etc. is also a crapshoot.
Very much edge cases though, unless you’re dealing with a lot of randos. A workshop I used to share had a wall covered with sawstop ‘trophies’, due to people doing weird stuff.
I've triggered one by touching the blade too soon after it has stopped. There is a short delay between when the blade stops and when the brake is disabled. I've also had one trigger on a heavy miter through some gnarled 8/4 walnut.
Actually not.
My handguard saw will do as well as the sawstop non-destructively (independently tested and verified, so you don't have to take their word for it).
They do it (basically) by predicting whether your hand will touch the blade, rather than waiting until it does touch the blade.
If you wait until someone actually touches the blade, then yes, you have to operate very very fast. That is unavoidable due to physics, as you say.
But if you can gain 100ms or 250ms by proving a 100% probability that the hand will touch the blade before the person can stop it, you now have a lot more time to stop the blade.
Ive looked at the saw you mention in another comment, and in all honesty Id much rather have a safety precaution that works based on very simple physics (like sawstop) than some black-box ai hand detection algorithm.
Have you considered that they've thought of this?
Seriously.
This is company producing high end sliding table saws that cost tens of thousands.
They've been at it for over half a century.
This is not someone producing a 299 saw as cheaply as possible.
They are a German company (ie regulated heavily) and have a ridiculous number of safety standard certifications that test things like "what happens when there is dust"
do you really think they haven’t thought of the obvious basic issues and figure out what to do about them?
if so, what evidence do you have that this is true?
(Also I think you don't understand European requirements on dust extraction and allowed exposure to wood dust. This saw does not produce a meaningful anount of dust)
Finger movements are generally on the order of 1-2Hz, a hand holding a large piece of wood will generally be much lower than that, which means that at the hundreds of millisecond level most of the movement can be predicted from momentum alone. Something which identifies and tracks hands in a view and fits a second order model to the movement can likely predict accurately enough at that timescale to make for a meaningful safety improvement (especially because if it's non-destructive you can tune it to err more on the side of caution than a destructive option)
Holding a piece of wood and sliding it along a table saw (to cut it) is the canonical method for losing a finger, and you could definitely pick that out with a relatively simple bit of computer vision.
I used to have a house that backed up to a county park in Maryland. My shop was out back. I was working carefully at my sawstop (that is what I had back then), standing properly to the left of the kickback path and using a push stick and roller guides. I was just finishing a cut
A hawk decided to throw a dead animal at the window behind me hard enough to shatter it. I was startled and my hand moved enough for my palm to cross the top of the blade.
I would not have lost fingers most likely but it would have been very bad.
To your point accidents are not always foreseeable. Yeah some people work stupidly but plenty of times, It’s just random unexpected events.
also, the saws do not produce dust everywhere.
these are European saws. Dust extraction is not only required on the saw, It’s required by law in the workplace.
This saw will not operate unless the safety + extraction hood is in the proper position and dust extraction is hooked up
I can show you a video of an air quality meter sitting between the cameras and the saw hood if you want. The amount of particle change is minimal
The blade doesn't have to stop. Some saws have the entire blade assembly lower. If you walk the table saws at AWFS you'll see all types of different safety systems.
Depends on the system. This would be my second to last choice as an engineer. First choice should always be design the system so you can't get hurt in the first place - but nobody has any ideas on how to do that to a table say (or we have ideas but it no longer can do the job of a table saw and so must reject them). Second is to put guards in places - we have been doing that since at least the 1980s (probably before, but I'm not old enough to remember), but guards are not perfect and so people still can lose a finger even with guards used correctly (cheap guards often limit the functionality of the table saw by enough that everyone just removes them, but even good guards are not perfect). Only after the above would I look at stopping the system when a problem is detected. Last, but only if all of the above fails - is you put warning stickers on.
Let me emphasize: you should run the above list in order. If you can design a problem out then you are not allowed to put guards, brakes, or warning stickers on./
Most industrial machinery is designed with the above process. there is a lot of machinery from early days still around with out safety, but most industry has been adding guards and brakes to those were possible and replacing (machines from the 1950s are probably worn out anyway) the old stuff. Industry also has extensive safety training for the dangers they they cannot prevent other ways. The safety results for industry is much better than it was 100 years ago. Not perfect by any means, but much better and getting better [I was going to write every year, but random chance means some years there are more accidents than others despite the safety situation overall improving yearly]
An example might be railroads putting a derailer at the bottom of a hill to protect industry or businesses. The derailer is removed when servicing the line, but put back to protect the end of the line industry from run-away cars. Conclusion: they'd rather have run-away cars de-rail and have to recover them, then letting them damage a factory or business.
I would be glad to see better table saw safety mechanisms, though I'm skeptical that 1. This will actually happen 2. That patent is the only one that will wind up mattering.
I can't help but wonder if a big part of the reason the number of incidents is so high is because we're intentionally hyperbolic about risks when it comes to warning labels, for liability reasons. As an example, many appliances will warn that you can never operate them with the covers off and doing so can cause death or serious injury. Okay fine, sure, it's not necessarily safe, and perhaps you could indeed kill yourself by accident doing so. However, in practice it's bullshit. People do this all the time, and you pretty much have to sometimes. How the hell are you even supposed to troubleshoot without being able to see what's wrong? Just guess?
So sometimes when it comes to warnings it's easy to empathize with the person who didn't take them very seriously, as we're pretty much conditioned to take warnings like this with a grain of salt.
Though honestly, when it comes to using a table saw, the thing I'm actually afraid of is kickback. Amputation risk is still very serious of course, but I feel safe enough with the many layers of mitigations I already use. I don't want to fall into complacency, but I also don't think I'm going to lose sleep over not having a SawStop table saw either. (I am not using my table saw often enough for it to be a terrible concern anyways.)
My grandfather is 90, he was a woodworker, he lost two fingers to a table saw. Few woodworkers of his age have 10 fingers. Workshops are much safer today and woodworkers can expect to end their career with all their fingers. That SawStop thing is one of the many things that can contribute to it.
The idea that safety features cause complacency has been debunked several times. Statistically, well designed safety features or equipment reduce accidents, even if it may cause some people to get complacent.
And you are right to be afraid of kickback, and one of the risks associated with kickbacks is inadvertently touching the blade, that is the issue SawStop is designed to address. The blade guard helps too, but AFAIK, there are many instances where you can't use it.
> The blade guard helps too, but AFAIK, there are many instances where you can't use it.
Blade guards are rarely used in shops I've worked in. I've even worked in a shop that removed the riving knifes on their saws as they got in the way of certain cuts and they didn't want to spend time taking them on and off.
Stumpy Nubs over on YT gave some testimony where he believes that a well-made blade guard could prevent most injuries. He believes that it's a culture around not using them (or poorly-made ones) that is the source of most injuries.
The blade guards on the cheap tablesaws are awful and everyone removes them. The good table saws come with guards that work much better (but still not perfect sometimes you have to remove them but most of the time they work well). You can buy a new table saw for under $100, a good blade guard can be bought separately for $300 so you see why a lot of saws have cheap guards. (note that the cheap tablesaw too light duty to support the good guard)
Plunging cuts, and 'cove' cuts. Also smaller blades like dado stacks.
With a cove cut you move the fence to about a 30 degree angle to the blade, to get an elliptical cove along the length of a board. It's a rare thing to need. But if you really need a wide cove, it might be hard to get a router bit to do that.
Very beginner woodworker here, but dados(or any kind of groove are the ones that immediately come to mind. Essentially anything that has the work piece going over the blade, but not cutting through completely.
You can keep the riving knife for those cuts, it causes no issue. just can't use the blade guard. I honestly can't imagine a cut that would require the riving knife off.
Dado stack. It's a smaller diameter than the blade. You'd have to be pretty lazy to not just reinstall the riving knife when you put a normal blade back on, but I could see that happening.
I think people get complacent and if it a cut that one does fairly regularly, I could see someone saying on the 1000th cut "eh lets keep it off for this one time" and then it just becomes a thing.
> I can't help but wonder if a big part of the reason the number of incidents is so high is because we're intentionally hyperbolic about risks
I've work in multiple production furniture shops and that has not been my experience. People are just moving fast, trying to get stuff done and things happen. Also, training safety in a non-educational setting is tough.
Yeah, see, I actually just simply don't know what the breakdown of the 30,000 incidents per year is. I would've guessed a large number of those incidents were from hobbyists and not professionals, and I would guess that the mistakes hobbyists make are different in origin from the mistakes professionals make, even if they have common threads. If it so happens that it's actually mostly professionals losing fingers, then I'm barking up the wrong tree with this.
I'd wager the opposite. A hobbyist will typically have a healthy fear of a table saw because one of the first things someone learns about a table saw is that it will fuck you up without a moment's notice.
A pro in a hurry? Not so much. It's the pro that's gonna remove the safety guard and riving knife, be invested in expensive blades they don't want to replace if the cartridge goes off accidentally, etc., etc.
The pro knows the safety stuff too, but they get into a groove (we call it the zone in programming) and start to take shortcuts to go faster without noticing their fingers are getting closer and closer to the blade.
The hobbyist doesn't enough to get into a groove and so won't have that happen. However the hobbyist is doing many different cuts and so doesn't always remember how to do each safely.
I’ve also seen many hobbyists do cuts on table saws that seem to encourage danger and then they stand right in the way too. Then they complain that “no one could have predicted this.”
The worst one I’ve seen is someone cutting circles on a table saw (already normally a no) with their hand behind the blade on the side that pulls you in instead of cutting (the kickback side). And it pulls his fingers right into the blade. (Saved by SawStop though.)
Heathy fear does not mean they know how the saw works at all. So I’d say both sides are apt to lose fingers.
Perhaps it's a bathtub curve, but dollars to donuts you'll have an easier time convincing a newbie to not do dangerous shit than someone more experienced. Beyond just doing stupid shit (plunge cuts, circles, arguably dados, whatever) there's professional pressure. Take a look at the whole stone countertop industry (very) slowly coming to terms with silicosis.
Either way I think Sawstop is great. As a hobbyist I wish it were cheaper. Although to be fair a big part of the cost is that Sawstop doesn't sell low end saws — that's nothing to do with the safety tech.
> I can't help but wonder if a big part of the reason the number of incidents is so high is because we're intentionally hyperbolic about risks when it comes to warning labels
Chainsaws have about the same number of annual ER visits as table saws. It's common to see someone using a chainsaw without most of the recommended safety gear. In those cases, it's probably money.
Does making tools more expensive really benefit anyone other than the companies which own the patents which make them more expensive?
Of these 30,000 injuries per year, how many happen when the blade guards are removed? How many happen when a push stick is not used? How many happen when a person stands in the direction that a piece of wood will be thrown by kickback? Once all those are subtracted are there enough injuries to count?
What if all tablesaw injury cases were tried by a jury of shop teachers?
The best advice I got in shop class was to slowly and quietly count to 10 on my fingers before throwing a power switch and in doing so to envision the operation from beginning to end and all the forces which would be involved, and to remind myself, that I wanted to be able to repeat that cut when the power was turned off.
SawStop goes on about how they will license their patent, but the licensing being offered is a very narrow one and doesn't seem to include the entirety of their patent portfolio, and they have fought very hard to keep tools with similar capabilities out of the U.S. market claiming patent infringement.
> Does making tools more expensive really benefit anyone other than the companies which own the patents which make them more expensive?
I would pay thousands to avoid losing part of my hand. The increased price is a very good value, tens of dollars.
Look at rearview cameras. Cheap tech. Used to be a 1000+ USD option. Now that they are government mandated the manufacturers figured out how to include them for a couple hundred dollars.
Price goes up, but just a little. Money well spent.
> I would pay thousands to avoid losing part of my hand.
I cut off the distal segment of my right thumb on a table saw in 1995. The initial bill, before I disputed it and received a "professional courtesy discount", was $25k.
So, you can pay a relatively small price to avoid losing part of your hand, or you can gamble that it will never happen, and then pay a high price for losing part of your hand.
Pretty simple choice to me.
ps.
Doctor: what do want to do with the rest of your life?
Me: well, I'm a programmer right now, but I'd rather be farmer
Doctor: I know a lot of farmers with less digits than you still have, and you'll still be able to hit the space bar as-is.
In effect, a SawStop system is like a one-time health insurance payment that prevents you from getting injured in the first place, only without jacking up the price because you used the tool in someone else's garage.
Good thing you and the doc weren’t on opposite sides of the tabs v spaces discussion.
Ed: The fact that you can hit the space bar with either hand, whereas the tab would require changing your keyboard layout is not a consideration I had previously considered in this debate.
To be fair, other companies haven't been trying very hard. I hate Felder for this. They have their own tech to drop the sawblade when they sense fingers. And they use it as a form of market segmentation, only offering it on their $30k+ tablesaws and not on their less expensive ones.
> The best advice I got in shop class was to slowly and quietly count to 10 on my fingers before throwing a power switch and in doing so to envision the operation from beginning to end and all the forces which would be involved, and to remind myself, that I wanted to be able to repeat that cut when the power was turned off.
It's great advice, but injuries tend to happen when people become complacent with the operations.
You're not required to purchase them if you don't want to. Personally, I have a stopsaw. It has never triggered, so beyond initial purchase price, it hasn't cost me a cent extra, but in the unlikely case where I do something dumb or have an accident, I feel better knowing it won't be life altering and all I'll need to do is replace a blade and a $99 cartridge. That's worth it to me.
likewise, but also worth noting that the saw stop saw is just a...nice saw. Better than the old delta I used to have, better than the powermatic 66 that I grew up using. Probably not as nice as my buddy's $20k sliding Felder saw, but...for the price, a Sawstop is a nice tool and highly competitive in build quality.
This is Stumpy Nubs argument (YouTube: https://www.youtube.com/watch?v=nxKkuDduYLk); that patience, forethought, and use of a blade guard and other tools would prevent most injuries. I'm in agreement.
But I don't think that companies are trying to make the tools more expensive. In fact, it was the opposite. SawStop sold high-end saws, other manufacturers did not want to adopt the technology because of the cost it added.
The issue of proper saw safety and use of sawstop technology are two different issues, I believe. And while I agree, the proper safety procedures you cite should be used by everyone, they aren't. In fact, they often aren't. And we can sit here and shake our fingers, but it won't change the overall culture around them. And I think that's the conclusion that regulators have come to as well: They're not going to get people to always use their blade guards or count to 10, so they'll mandate adoption of a technology that mitigates the risk due to people not following directions.
Regarding the licensing, I think that's been addressed by others elsewhere. But in short, SawStop defended their patents in order to license the tech. When the government moved to mandate it, SawStop said they wouldn't enforce their patent, but they're not handing the tech over either. Other companies are free to develop their own method without running afoul of SawStop's patents, or they can license SawStop's tech. To me, it seems like a fair approach that both protects their investment while not putting themselves in a morally questionable position in taking advantage of the upcoming regulation.
I'm suggesting that people should have a sense of personal responsibility when operating potentially dangerous equipment, and that a person should not be required to pay extra for a business or hobby just because some well-to-do patent lawyer has come up with a business model which has an end-game of requiring that patents from his company be required in products.
You can’t control what sense of personal responsibility people will or will not have. So saying that they “should” have it means absolutely fuck all.
A requirement for this safety feature would be enacted in order to prevent a large number of accidental mutilations. It might make money for certain people and they might push it for that reason, but that’s not the main purpose for enacting it.
I look forward to your complaint that you’re forced to spend money on seat belts you don’t need.
Ah personal responsibility! The magic bullet that mitigates all accidents.
All of your personal responsibility will vanish the instant you injure yourself horribly - then you'll be wholly reliant upon numerous other people who will have to deal with the horror of what you've done to yourself, or else be delayed in receiving their own care because of it.
> Of these 30,000 injuries per year, how many happen when the blade guards are removed? How many happen when a push stick is not used?
Seems like you don't buy into the swiss cheese model of accidents. Because other safety mechanisms and good practices exist, it doesn't mean that there's not reasons to add additional safety. In aviation, we always blamed the pilots for a long time, and it wasn't entirely wrong. However, no matter how much we told pilots "stop crashing and dying!!" they didn't seem to want to stop.
This is there for the day when other things go wrong-- when a tired operator reaches for something he obviously shouldn't; when a blade guard is out of place and someone slips; when someone who isn't sufficiently trained doesn't realize he shouldn't use the table saw.
> Seems like you don't buy into the swiss cheese model of accidents. Because other safety mechanisms and good practices exist, it doesn't mean that there's not reasons to add additional safety.
I think it's reasonable to say "we have done enough" at some point though. We can debate where the point is, but safety is not an unalloyed good. It has a cost, and reasonable people can disagree over whether a particular safety invention has enough ROI to justify its existence.
For example, we wouldn't countenance banning all motor vehicles even though we could eliminate all car related deaths with that one simple trick. We would get a fair bit of payoff, but the cost would just be too high to justify it. Similarly, if we could inflict a very minor cost on everyone in the world to prevent one death per year, that would be too low of a payoff even though the cost is very low.
So yes, we can always add more layers of defense against accidents (or security incidents). But eventually, the juice isn't worth the squeeze and you stop. So I don't think the Swiss cheese model really can justify any particular intervention by itself; you have to evaluate the specifics of whether the particular intervention is worth it.
> I think it's reasonable to say "we have done enough" at some point though. We can debate where the point is, but safety is not an unalloyed good. It has a cost, and reasonable people can disagree over whether a particular safety invention has enough ROI to justify its existence.
That has to be a point in time decision though. Closed circuit TV backup cameras in cars have been possible since I dunno, probably the 70s, certainly 80s technology could have done it; but they weren't a reasonable intervention (outside of say armored cars for currency transports) until more recently as cameras and displays have gotten less expensive and quality has improved. Also helpful as modern vehicle design has resulted in significantly reduced visibility compared to the past, but that's a rant for a car article :P
> So I don't think the Swiss cheese model really can justify any particular intervention by itself; you have to evaluate the specifics of whether the particular intervention is worth it.
You don't need to prevent too many maimings to pay for a whole lot of these and their occasional consumables.
Sure, risk homeostasis will claw some of the benefit back, too.
Yes, they did. They even tried to legislate against SawStop. See "H.R. 8181: Preserving Woodworking Traditions and Blocking Government-Mandated Monopolies Act"[1] Didn't go anywhere.
There is supposedly woodworker opposition.[2] "Many woodworkers argue that the implementation of SawStop technology has disrupted traditional woodworking practices. Some feel that it has altered the craft in a negative way by making it less reliant on skill and attentiveness, instead placing an emphasis on technology to prevent accidents. This shift in focus is seen as a departure from the fundamental principles and values of woodworking." However, no actual woodworkers are quoted, and the author has a tool store, so this is probably astroturf PR. That web site is addressed to people with a semi-religious attitude towards woodworking, not to working carpenters or cabinetmakers.
(Having used circular wood saws, I am all in favor of blade-stop devices.)
> "Many woodworkers argue that the implementation of SawStop technology has disrupted traditional woodworking practices. Some feel that it has altered the craft in a negative way by making it less reliant on skill and attentiveness, instead placing an emphasis on technology to prevent accidents. This shift in focus is seen as a departure from the fundamental principles and values of woodworking."
Wow. This is basically: real men enjoy getting their fingers cut off.
Ideologically speaking, it's the same sort of people that opposed seat belt laws in the 1980s on the grounds that they'd encourage risky behavior by drivers. (They don't.)
#2 is becuase woodworkers as a group are fairly conservative.
TTI and friends were very effective at riling them up. I belong to a number of significant woodworking forums/etc, and have watched the manipulation over the years firsthand.
This was mostly in the form of "big daddy government wants to make you pay for more saws because of dumb people", so the take they have there around the craft itself is pretty funny.
It's so silly. The saw stop doesn't reduce the amount of skill needed to use it, and you're still free to be as attentive as you like. If they really followed this to its logical conclusion, they'd be using unpowered stone tools to do woodworking.
The difference between the accidental damage a knife can do versus what a circular saw can do is night and day. And I say this as someone who needed surgery after cutting through a tendon with a knife. :(
Old school radial saws, for example, basically don't exist anymore at the consumer level. They were simply too dangerous. Slider-type miter saws have almost completely replaced them.
Personally, I would even go so far as to suggest that weekend woodworkers should avoid even having a table saw, period.
The main problem with table saws is that they become a "do all" machine even for those kinds of actions that really shouldn't be done on it. You're already at the table saw, and it's often really convenient to just "sorta kinda" bodge something up on the table saw rather than doing the safe thing and changing the blade, putting together a real jig or using a completely different tool.
If you have a track saw or a cheap CNC instead, the danger level is way, way lower, and the result is probably a lot better.
Radial arm saws vanished because they were a compromise solution that slider miters made inferior. They are pretty safe as the blade is constrained to travel along the arm for cross cuts and for rips is locked in place. The usual problem is simply stalling the saw. Rip cuts can definitely kick back if you don’t take the time to set them up right including the guard and anti kickback device. They can do it all, cross cut, compound miter, rip, dado. There were some sketchy shaping attachments I’d be hesitant to use. But the main problem is they are large as a big table saw and the changeover time. A table saw and sliding miter is the way to go now. But I still own a radial and if I had the space in my shop would set it up Norm Abram style.
Have you checked recent legal cases against gun manufacturers? Some are not too far removed from suing a battery manufacturer because someone took the acid from a battery and used it in an attack?
Traveled to New York City or the U.K. recently? Check your pocket for a locking blade, or an assisted opening knife before-hand.
The difference there is they funneled a lot of marketing dollars into pseudo education and astroturfing campaigns to create a sense of hysteria that the boogeyman was coming for the guns, specifically the now dizzying array of AR-15 derivatives and pistols.
That essentially contributed to a gun buying bubble and solider cosplay.
I think the idea is that if someone advertizes their saw as safe, but it isn't, then there should be some liability. Like if you make a fake safety saw or imply its much more safe than it actually is you should get in trouble.
But surely there must be some middle ground between a company making a fake safety saw, and a good faith effort that isn't quite perfect.
The claim was "The saw manufacturers all blew off SawStop because they were worried that they would now be liable for any injuries which still occurred."
Meaning that table saw manufacturers were worried if they implement SawStop like safety feature, and they advertise their saws as safer they become liable for times when the technology does not work.
So yes, you appear to be correct what saw manufacturers say about their safety now, but that's not the point we are discussing. The point is that if they add a SawStop like feature and advertise it then they would be talking about the safety of their saws.
The alternative approaches from other industrial saw manufacturers that are "non-contact non-destructive" are interesting:
- cameras and machine learning used by Altendorf "Hand Guard": https://www.altendorfgroup.com/en-us/machines/altendorf-hand...
- inductive proximity (same science as Theremin[1]) used by Felder "PCS Preventative Contact System" : https://www.felder-group.com/en-us/pcs
- SCM "Blade Off" (not sure of detection method ... looks like inductive proximity) : https://www.scmgroup.com/en_US/scmwood/products/joinery-mach...
But I've heard reports from 3rd-parties that Altendorf's camera detection method is unreliable/glitchy and doesn't work as well as Felder's system. Maybe Altendorf fixed the bugs.
Also, Altendorf's philosophy of using cameras & ML instead of inductive proximity reminds me of Tesla's philosophy using cameras instead of LIDAR (Waymo).
[1] https://en.wikipedia.org/wiki/Theremin
EDIT ADD: >I'm not sure how comparable these alternatives are when two of them are "request a quote" kind of pricing, and the Altendorf is $7000+
My comment was about "industrial saws" so they're definitely not realistic alternatives to buying a jobsite SawStop for homeowners. I added italics to the adjective "industrial" to clarify this.