Thread: Sawstop

Originally Posted by Midnight Man

It should not, as they won't complete the circuit (being such a small item).

If you were holding the grub and hit the blade, then, yes.

Still unconvinced - so the "sausage" dummy that SawStop use to demonstrate the effectiveness of the technology is dependent upon the size of the "sausage?" or is a "pinky finger" less likely to be detected? I think not.

Originally Posted by Mobyturns

Still unconvinced - so the "sausage" dummy that SawStop use to demonstrate the effectiveness of the technology is dependent upon the size of the "sausage?" or is a "pinky finger" less likely to be detected? I think not.

Look at all those demos closely. You will see that the sausage is being held by a human with skin to sausage contact. Thus there is electrical contact between the person's body & the blade.

Not defending SawStop - just pointing out that you need to be critical of the right things. As per my post above, I'm unimpressed with the false firing I experienced and their subsequent treatment of my claim for a replacement cartridge. Also, the saw is not a total panacea as some seem to think - e.g its not protecting against kickback. I'm sure it has saved some people from horrible injuries, but there are other alternatives for many folk - for me it will eventually be a Euro Slider; arguably a safer & better alternative.

The big problem, as I see it, with SawStop is the frequency of false firings, and the high cost of reinstating and downtime.

This appears to be a far better system:
PCS(R) Preventive Contact System | Felder Group
I understand that PCS was developed as a joint venture between major Continental saw manufacturers and that it will soon be available from many members.

Remember, a sliding top panel saw already has a 40% better safety record than a US style saw bench. And the PCS system looks like it will work equally well on a saw bench or even a router table.

I asked an electronics engineer friend to have a look at it and he said that whilst they do not give a lot of specifics, it seems that it may be a derivative of the sensing technology used in bar code readers at supermarkets, etc, or similar.

Originally Posted by GraemeCook

The big problem, as I see it, with SawStop is the frequency of false firings, and the high cost of reinstating and downtime.

This appears to be a far better system:
PCS(R) Preventive Contact System | Felder Group
I understand that PCS was developed as a joint venture between major Continental saw manufacturers and that it will soon be available from many members.

Remember, a sliding top panel saw already has a 40% better safety record than a US style saw bench. And the PCS system looks like it will work equally well on a saw bench or even a router table.

I asked an electronics engineer friend to have a look at it and he said that whilst they do not give a lot of specifics, it seems that it may be a derivative of the sensing technology used in bar code readers at supermarkets, etc, or similar.

The Felder PCS system certainly adds a belt-n-braces approach to safety, with the benefit of NOT destroying a blade and also being able to get back to work very quickly as there are no cartridges to replace.

Griggio have had this system available since 2015. It would be interesting to see if Felder have licensed or purchased this from them. (edit - Griggio went into receivership in 2018. Maybe someone has bought their IP)



Also interesting is the SawStop patents start expiring in 2021. So we may see a re-introduction of the Bosch REAXX, and possibly similar systems from others, over the next few years. The PCS is, as I understand it, an expensive option & unlikely to be offered in the low end (such as Hammer) for quite some years.

(Edit 2)

And here is one Altendorf is working on:

That PCS system looks nice indeed.

I dont think it will see its way into the sub-$2000 market, but we can hope!

Patents are overall a very good thing. They look evil, but they do reward ingenuity. Shame about the trolls, bogus "obvious" patents, and BS "re-patenting" via trivial modifications.... that part of the system needs fixing, badly.

The sawstops don't just gain kudos from the safety aspect - their finish is incredible. A beautiful machine overall. The cheaper saws are vastly inferior.


It would be lovely to see a PCS system in the lesser saws, its exactly where its needed. Some of the YouTube videos I watch of various presenters are horrifying.

Originally Posted by woodPixel

The sawstops don't just gain kudos from the safety aspect - their finish is incredible. A beautiful machine overall. The cheaper saws are vastly inferior.


It would be lovely to see a PCS system in the lesser saws, its exactly where its needed. Some of the YouTube videos I watch of various presenters are horrifying.

The SawStop offerings are certainly of much higher quality than many of the offerings in that market segment.

I agree that overall the lower price point market segments do require "more protection systems," though that is most unlikely to occur due to market dynamics.

One report I have read on "Table Saw Injuries" states that many users "may discover dangerous and difficult operations only by actually experiencing near accidents or problems." This highlights a general lack of knowledge, education, training and suitable supervision for new users of potentially hazardous tools & machinery in non-workplace or non-educational institution settings., i.e. the DIY / hobby segment. This is exacerbated by the disappearance of "sub trade" course offerings from the old TAFE system, for wood and metal "trades". Having others who may not be considered to be "qualified to offer training" providing questionable "training resources" to others is not helpful.

The report highlights the value of the SawStop "cartridge data" as it provides a better understanding of the mechanisms of injury, and data on "time between contact and detection," the type and severity of injury but qualifies the accuracy / veracity of "user supplied" data. However it points out that the database data is from customers filling out a survey and supplying the cartridge for analysis. It also highlights that "Most of the incidents in the database occur at a "workplace or school," since "most SawStop table saws are sold to professionals, schools and government entities." Therefore the data has a strong "workplace" bias and is not overly representative of the DIY / hobby user segment (lack of training & supervision?) or the injury scenarios typically present in the non-workplace environment.

Another report states "one study found that amateur status was a significant predictor of injury" in hazard / risk analysis. We already know that yet many users choose not to seek out training, or it is simply not available.

Yes SawStop or similar technology is a beneficial engineering solution to "prevent / minimize" injury, it is not "fail safe" as SawStops data base shows many events well outside their quoted "time between contact and detection," and "activation times." That is potentially a natural variable influenced by many factors including user hydration, sweating, contaminants on fingers that may prevent detection. Are things like super glue or other glues on the area that makes contact with the blade likely to interfere with "detection times?"

Detection systems and engineered solutions to remove the hazard from the operator (dropping the saw blade etc) are certainly very beneficial. However an over reliance on that technology "working" and / or not adopting recommended work practices significantly increases risk.

The report states "The database in this study included 1,316 incidents since 2005 (to 2014)"

So after reading everything I've read here and to sum it up.

The SawStop technology works but it is far from perfect.

A year ago, (at AWFS) in a discussion with the department head at the community college where in 2005 I helped install several SawStop table saws. . . . I asked "Have there been any blade drops?" His answer, "Dozens." He went on to say that most were caused by hitting metal. He said that hitting a measuring tape was a major culprit.

The hitting a measuring tape is the one that drives me nuts. Being the semi logical idiot in the family, I don't understand how that is possible. Then I really thought about it. I use a tape to set the distance between the fence and blade for precision cuts. Usually I'll rotate the blade by hand to an ATB / Right tooth and align that tooth with the tape to set the fence. (The calibration of the fence ruler changes with every blade change. Especially on a left tilting saw.) I'm guessing here but the blade moving by hand and touching the metal tape activates the blade drop mechanism. But then the flesh is in contact with the blade and moving the blade, shouldn't that alone drop the blade.

I guess the only answer is just "far from perfect". But it works and saves fingers.

Originally Posted by Mobyturns

The SawStop offerings are certainly of much higher quality than many of the offerings in that market segment.
I agree that overall the lower price point market segments do require "more protection systems," though that is most unlikely to occur due to market dynamics.
One report I have read on "Table Saw Injuries" states . . . . . .]

Is that report available on line?

Originally Posted by rrich

I'm guessing here but the blade moving by hand and touching the metal tape activates the blade drop mechanism.

Nope - the mechanism will not fire UNLESS the motor is running and the saw is in the (default) protected mode. Simply rotating the blade is not sufficient.

For a tape to activate the cartridge it must be pushed into a running saw blade.

Originally Posted by RossM

Look at all those demos closely. You will see that the sausage is being held by a human with skin to sausage contact. Thus there is electrical contact between the person's body & the blade.

Not defending SawStop - just pointing out that you need to be critical of the right things. As per my post above, I'm unimpressed with the false firing I experienced and their subsequent treatment of my claim for a replacement cartridge. Also, the saw is not a total panacea as some seem to think - e.g its not protecting against kickback. I'm sure it has saved some people from horrible injuries, but there are other alternatives for many folk - for me it will eventually be a Euro Slider; arguably a safer & better alternative.

No argument about it.
There’s a good reason why every cabinet and joinery shop I’ve worked in has a sliding table saw.
They’re better, and they’re safer, end of story.

Originally Posted by BobL

Is that report available on line?

Bob the report is "Table Saw Hazard Study on Finger Injuries Due to Blade Contact" - UL LLC, well worth the read.

Back in 2010 I downloaded NEISS & CPSC data initially looking for "Wood Lathe Injuries" whilst researching my safety articles that were published in UK Woodturning magazine. Fortunately there is a heavy emphasis on "table saw injuries" but almost nothing on "wood lathe" due to coding issues at collection in ED's and within the datasets. The OSHA investigations are available online too.

"Executive Summary
The intent of this research was to understand the circumstances that may lead to hand/finger contact injuries for operators of table saws and help identify critical parameters that would define the hazard level. For the specific hazard of hand/finger coming into contact with a spinning saw blade, two critical parameters were identified: first, hand approach velocity, as an appropriate metric for the movement of the hand/finger toward the spinning blade; and second, a medically guided estimate of maximum cut depth of the finger that would help distinguish between simple and complex lacerations and provide a positive impact on reducing the severity of hand/finger injuries. Based on the research described within this report and the intent of reducing hand/finger blade contact injuries for table saw operators, the following relationship between approach speed and depth of cut (Figure 1) is recommended:"

"the database is unique by virtue of the data extracted from an electronic cartridge that is part of the safety system, and so the SawStop database is the key source forthe approach-speed set point recommendation"

If you look critically at the "SawStop Finger Demonstration - move over hot dog!" in which the inventor Steve Gass uses his own finger his "hand approach velocity" is much lower and positioning of the "subject finger" very different than in a "real life scenario." SawStop Finger Demonstration - move over hot dog! - YouTube

UL_WhitePapers_Tablesaw_V11.pdf

I'm definitely a supporter of a holistic approach to safety - hazard elimination - risk analysis - and a comprehensive suite of actions to eliminate / minimize potential harm.

Over reliance on one action - in this case a very sophisticated "engineered solution" to remove the hazard from the operator - is counter intuitive. The "lesser actions" - the administrative actions - training, education & supervision - also play a significant role in harm minimization.

ULL and others raise those matters and highlight the "complacency" of SawStop users with associated events such as potential kickback. Some suggest that the "near miss" rate actually increases with users of similar technologies. The OSHA data identifies four fatalities and numerous injuries associated with table saw kickbacks in the past few years - the SawStop technology will not prevent injury, nor minimize the harm from a kickback event - except in the event that a part of the user actually triggers the cartridge - secondary to the kickback event.

Originally Posted by riverbuilder

No argument about it.

There’s a good reason why every cabinet and joinery shop I’ve worked in has a sliding table saw.

They’re better, and they’re safer, end of story.

So true.

Originally Posted by riverbuilder

No argument about it.
There’s a good reason why every cabinet and joinery shop I’ve worked in has a sliding table saw.
They’re better, and they’re safer, end of story.

River builder, I’m genuinely interested in what makes them safer in a ripping cut. Do you know of a good a link to a video on how to make repeated ripping cuts from a board (not sheet goods) on a slider? Your assertion is widely parroted by those who have/had a slider so see no reason to doubt it. I see the benefit to cross cuts and breaking down sheet goods, just not ripping.

However the only sliders I’ve seen in action are on YT, and holy smokes, there’s nothing safe about what they do. But knowing how so many “makers” use normal cabinet saws, I would imagine that’s not really a fair measure of a slider’s safety benefit.

Hi LanceC, I’m presuming , perhaps incorrectly, that you mean rip cutting solid timber along the grain using the sliding table?
If that’s the dangerous technique you’re meaning, I wouldn’t know because I never do it nor ever have.
this is what I do:
1. fit the appropriate blade and raise it fully up.
2. Remove the crosscut fence and lock the sliding table.
3. set the fence forward to be just past the centre of the blade.
4. set the fence to the width required.
5. rip the stock as required.

Im not sure what you have seen on YouTube as I’ve never watched stuff on tablesaws, I can only comment on my own experiences over 40 odd years and what I’ve been taught by the old man.
I know there’s plenty of jingo out there on the safety aspects of this saw or that, but,in my experience, I’ve seen more accidents and kickback events on those sawstop type tablesaws than on sliders, but I’ve probably used and seen sliders a lot more too.

edit: I found this from derekcohen,a member on the forum, he has a jig where he uses his sliding table to rip. Underbench cabinets