SawStop: Will it trip.

[Thomas Wilson]

I promised a video showing things that cause or don’t cause brake actuation. I made the video. Now I have to see if I can upload it. Let me know if you can view it


https://www.youtube.com/watch?v=DqZWvZ1pkQo

[Frederick Skelly]

Thanks Tom. That was interesting.
Fred

[Brian Tymchak]

Thanks for taking the time to create that video Tom. Very informative.

I believe it was you that posted in the original thread that pine pitch pockets may cause a trip. I think the thread with your post has been deleted so I can't be sure. Where I volunteer, I had a brake fire while I was cutting some low quality pine. We never figured out what the cause was. If it was you that offered that info, can you provide more info about the pitch pockets or provide a link to more info?

Thanks!

[Bryan Hall]

Looks like cam at black tail studio just had an activation on some foam board? I wouldn't have expected that.

[Lee Schierer]

Looks like cam at black tail studio just had an activation on some foam board? I wouldn't have expected that.

Having worked with cutting foam insulation board on a table saw, I can assure you that it can generate a significant static charge during the process. I would suspect that a static charge could trigger the saw stop device as it could appear to be a change in capacitance. I don't own a Saw Stop to test this theory.

[Darrell Bade]

I've cut foam board on mine ........... in bypass mode ........ just seemed like the thing to do with an unknown material.

[Mark Gibney]

Good video Thomas. It addresses some concerns I had about the Sawstop. I'm now happier to buy one.

[Thomas Wilson]

The speed of change component in the actuator trip means that testing the material with the saw off is less sensitive than actually actually cutting the material. I should also demonstrate cutting in bypass to show the light signals indicating whether the material would have caused a trip. I will work on that.

There are lots of reports false actuation in plexiglass, foam, treated pine, and other materials that could be tested in bypass. Foam insulation with metallized Mylar coating actuates the brake reliably. The others must require some special circumstances. I have cut the treated pine and polycarbonate without tripping, lots of treated pine. A video might be useful.

Someone asked about the false actuation in dry wood that was attributed to pitch. That story was posted on the SawStop Users Group on Facebook. It was, like this, an unexplained trip in which the user was doing everything right. They did not “prove” in my estimation that it was pitch. They just removed all the imaginable other causes. It did seem to be caused by a particular piece of wood. SawStop did become involved. I have not searched for the thread.

To those who think the trip mechanism does not prevent serious injury, I hope you will seek out a SawStop demonstration in your area. They have resumed having them. One is scheduled today at the Knoxville Woodcraft store (may be cancelled due to snow!). Also, people tend to post pictures of their saved fingers. Most only require a bandaid, not surgery, no stitches. Look them up.

[ChrisA Edwards]

Thank you for the video. Much more info than I was aware of.

I've had one dry trip, on a Dado blade, didn't damage the blade as it never rotated.

Since then, I tend to use the override when I have any doubt about the material I'm about to cut.

[Thomas Wilson]

I've cut foam board on mine ........... in bypass mode ........ just seemed like the thing to do with an unknown material.
I do a test cut in bypass too. If the test shows no actuation, I do the production run, if there is one, in normal mode. I may put on a cheaper blade than the normal Forrest blade. I risk the financial loss of a false actuation over the loss of protection by running in bypass. It is my choice. One other factor is that it is a multi-step process to engage the bypass mode. You have to go through the bypass process each time you turn on the saw. It is much faster to run in normal mode.

[Thomas Wilson]

Thank you for the video. Much more info than I was aware of.

I've had one dry trip, on a Dado blade, didn't damage the blade as it never rotated.

Since then, I tend to use the override when I have any doubt about the material I'm about to cut.
Two things indicate that this may have been a blade clearance issue. You had just installed the dado set and the trip occurred immediately on start-up. With a dado set, it is somewhat harder to check. I find I have to move the adjustment screw for the dado then move it back for the 10” blade. I am aware of the potential problem and check clearance every blade change. Nevertheless, I hold my breath every time I fire up the saw after a blade change.