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SawStop doesn't detect when I touch lightly on the blade?

7K views 32 replies 22 participants last post by  TheFridge 
#1 · (Edited by Moderator)
I just got my SawStop PCS. First, amazing attention to detail in both the product and the assembly instructions.

With the saw off, when it detects your finger the lights flash red. I am surprised that merely touching the blade with light pressure doesn't cause it to start blinking red. Only when I press down harder does it blink. I took a video:



Is this working as intended? I tried two different blades. Same thing.
 
#2 ·
I've always been concerned about the SawStop concept. You are sacrificing your safety to technology. Will it work as expected? Do I need to slap a wienie weekly, and pay the $180+ repair bill.?

I know I have to respect my blade, because it will not yield. What if I thought it would yield, like a SawStop, and it didn't?
 
#4 ·
I ve always been concerned about the SawStop concept. You are sacrificing your safety to technology. Will it work as expected? Do I need to slap a wienie weekly, and pay the $180+ repair bill.?

I know I have to respect my blade, because it will not yield. What if I thought it would yield, like a SawStop, and it didn t?

- RichTaylor
That seems like a silly argument. What are you doing where you expect the blade to yield? It's a safety feature for accidents.

Sorry OP, I have no idea.
 
#5 ·
That seems like a silly argument. What are you doing where you expect the blade to yield? It s a safety feature for accidents.

Sorry OP, I have no idea.

- JADobson
You misunderstood. I said my blade would not yield - and I know that. Therefore I respect it. My point was the failure of a system, like the SawStop. What if I trusted it, and it failed?
 
#6 ·
But what possible situation would there be where you would need to trust it? I'm sure every SS owner still treats their blade like it could hurt them. Even though the safety feature exists no one wants to actually use it. It's just for accidents which, if they happened on any other saw, could be catastrophic.
 
#7 ·
To the op, you should call saw stop. I have a pcs and I have touched the blade several times , when it is not moving, obviously, and it doesn't matter if I gaze it or touch it with more force, I always get the blinking red light. Natural moisture on human skin provides the transfer of the signal, is it possible your hands were extra dry or you had some glue on the point of contact on your fingers? Just theorizing why your reaction is different from mine and other experiences I have heard about.
 
#8 ·
You misunderstood. I said my blade would not yield - and I know that. Therefore I respect it. My point was the failure of a system, like the SawStop. What if I trusted it, and it failed?

- RichTaylor
What misunderstanding, you specifically said this "You are sacrificing your safety to technology. "

Just as ppg677 said, you are not less safe having a safety feature. And, as with air bags, with a SawStop you are not less safe if it doesn't work, than if you didn't have it at all. Though just like air bags, you want to make sure all your safety features are functioning properly. After all, that's one of the reason people buy SawStop saws.

Having a SawStop, I can assure you, I do not even think about the safety feature while using the saw. I do not take additional risks. Even if I were to factor that in while using it, the expense of a replacement cartridge and blade is reason enough not get sloppy.

To the OP, I think the problem may be the blade. It doesn't look like a SawStop blade. While it could be a reflection of the red insert, It looks like a red Fraud or Diablo blade. The red paint doesn't conduct electricity.

As a general rule, you don't use coated blades with a SawStop. Though check with them for details. I do use some red Fraud blades, but I remove the paint around the arbor hole so the large washers, that go on each side of the blade, make contact with metal on the blade and not paint.

It's probably not so much that you are pushing on the blade to get it to blink, as much as when you push, your finger flattens out and make a much better contact (more surface area). Though pushing could also make some sort of change at the blade to arbor contact point.

But the issue isn't really the connection from you finger to the blade, rather the blade to the arbor. Since, it appears you are touching the bare blade tooth. Though I think even some blades have clear coating. So perhaps there is something coating the blade tooth that is insulating it. This of course would only apply if this were a brand spanking new blade, since any cutting would quickly wear off a coating on the blade tooth.

If nothing else, put the SawStop blade on (if that's not what you are using) and redo your test. If it works as expected, then you have probably shown that it is the blade and almost certainly a coating on the blade that is the issue.
 
#9 ·
Hey ppg677,
I have an ICS and have passively tested the system by touching the blade many times. On the rare occasions where the red light does not go on I'll wet my finger and touch it again and the light goes on immediately. Have you tried other parts of your hand lightly as well or do you just push harder.

Clin's comment about pushing harder is on the same track, you are making better contact. Still it could be your blade; I'm not a blade expert but yours looks as if it has a paint coating and this could affect its conduction though the arbor.
There is a chance your saw may not be as sensitive as others but my thinking is if you changed your blades you'd see different results. Please follow up your post if you see better results with the stock or bare blades.
.
. .Marc
 
#11 ·
I have one and it detects even the slightest touch,. Kind of echoing a couple of things already said: call Sawstop, they have set a new standard in customer service and will be helpful. That said, I'm betting it's the coated blade causing the apparent reduced sensitivity. Try it with one that's not coated and see what happens (maybe the blade that came with the saw).
 
#13 ·
  • The blade you show in the video, is in dire need of cleaning, IMO. Does, or can, that buildup act like an insulator?...Might be worth testing with a multi-meter.

  • Another question to consider is, just how calloused are each woodworkers hands? I would think that callused hands would be more resistant to electrical conduction… How much more, who knows.
 
#15 ·
I use Frued blades pretty exclusively and I've also tested with my finger touching the blade. I've never had a blade touch not end in a red light.

My only problem with my saw stop is that it doesn't get used enough. Of course, I would have the same issue with any table saw I suppose.

For the OP - I would call SS just to talk to them about the issue. They've always been very good about answering all my questions when they come up.
 
#16 ·
I just tried mine a little bit ago. The light didn't come on until I licked my finger. My hands were extremely dry when I first tried it ans had to push a little harder to get it to come on. As soon as my finger was damp it came on with a very lite touch
 
#18 ·
I talked to SawStop tech support, and they said that the blinking red light is basically a sales/marketing feature. While it is activated by the same capacitive coupling, the software that controls the blinking red light is a simplified software path of the software that is active when the blade is actually spinning. As a software engineer myself, this makes sense to me.

Like airbags in a car, they run all kinds of diagnostic checks to capture errors or faulty hardware. Like airbags in a car, you can't be 100% certain that the system will work and therefore should drive safely.
 
#20 ·
I talked to SawStop tech support, and they said that the blinking red light is basically a sales/marketing feature. While it is activated by the same capacitive coupling, the software that controls the blinking red light is a simplified software path of the software that is active when the blade is actually spinning. As a software engineer myself, this makes sense to me.

- ppg677
It doesn't make any sense to me to create 2 separate software applications that are supposed to do the same thing, detect flesh. Why go through the effort to create two, and maintain two, when a single API can handle both situations?

If the software detects flesh blink the light and stop the blade if it's spinning. Seems simple enough to me.
 
#21 ·
Not uncommon with safety systems. One algorithm for control, the other for activation of the safety function. Software like that is all over the hydrocarbon plant I work at. I'm not that kind of engineer, but I just know it is out there that way.

One of those codes is probably only active when the blade is running, and includes the routine to trip the brake. I'm not sure how the hardware is set up in an SS, but the actual control/brake technology could be on a separate controller than the diagnostics and reporting. This is often done to keep the software shorter such that the refresh time as it works down its ladder, and then back to the top, is as short as possible. Another plant that I worked in that had PLC based control was this way. One processor for the graphics and display, another for safety critical functions. The safety critical function processor could guarantee a 10ms refresh rate, while the other which had more lines of code to parse could not. SS has a 5ms response time start to end, so that would seem to point to a dedicated circuit somewhere in there. That would be another driver to have two separate logic applications for the same blinking light.

Brian
 
#22 ·
Correct. Tech support said that when the blade starts running the "real" software is active which takes into account blade speed, is continually calibrating, etc.

In standby mode is likely just a dumbed down software loop. Makes total sense to me as someone who has written embedded control software before.
 
#25 ·
It doesn't make any sense to me to create 2 separate software applications that are supposed to do the same thing, detect flesh. Why go through the effort to create two, and maintain two, when a single API can handle both situations?
- ChuckC
Doesn't make sense to me either… particularly in an embedded system where you need to run skinny. Simple enough to just use the same detection mechanisms but disable the firing mechanism when testing. It also doesn't make sense that you would have a less than accurate detection system for determining if something will incorrectly fire the mechanism. I would be pretty upset if I tested something to see if it would fire, and it didn't blink - then have it fire when I started cutting because it was 'more accurate'. I guess they would sell more brake cartridges that way though :)

Cheers,
Brad
 
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