SawStop Brake Cartridge Trips

[Bob McBreen]

During the last week I tripped the brake on my StopStop three times. The first trip when I was cutting a piece of MDF that had been veneered on both sides using regular Titebond. The piece had been out of the press for over 48 hours. I thought that the glue must not have completely cured.

The next trip was three days later. The piece that tipped it was from the same batch of veneer and was out of the press for over five days. I didn't understand how it could have tripped.

The last piece was the next day it it was just a piece of MDF. I was shocked that it tripped the brake and called SawStop support. I was told that this has been happening frequently. The data from the returned cartridges shows that the MDF has tiny metallic strips as filler. The believe that the pandemic has caused the problem, both at the factories using new materials to make MDF along with retail stores having to use different sources to get product to sell. They said that a large cabinet shop had been tripping five cartridges per week and traced the start of the problems to the start of using a new supplier for MDF.

I will be running MDF cuts in bypass mode for a while.

[Patrick Varley]

Wow, thanks for the info. Haven't cut any "new" pieces of MDF recently, but I'm certainly going to consider using bypass mode as well.

Where did you get the MDF? Do you happen to know the manufacturer?

[Bob McBreen]

I was only doing a small job so I purchased a pre-cut 2'x4' piece of 1/2" MFD from Home Depot in Portsmouth NH. I will check if I can find info about the manufacturer.

[mreza Salav]

Wow, that has been a costly experience. Thanks for the heads up. Why would they use metal in MDF, that is abrasive on the blades regardless.

[Bob McBreen]

Three cartridges and two blades. I think that the third blade is ok, but will sent it out to Ridge Carbide be sharpened.

The SawStop rep said that some factories use the cheapest filler that they can get. He mentioned that the products that they have been able to trace have been made offshore.



Wow, that has been a costly experience. Thanks for the heads up. Why would they use metal in MDF, that is abrasive on the blades regardless.

[glenn bradley]

Ouch. Sorry that happened and thank you for reporting it here.

[Charles Coolidge]

Major bummer but so appreciate the heads up on this thanks.

[Bill Dufour]

I would contact homer depot. there is an implied contract that what they sell as mdf is mdf and it can be used and handled by ordinary wood working tools. I feel they sold you faulty "wood" and should reimburse you for destroyed tooling costs. It would be different if it just caused faster wear. Reminds me of formica as filler in cat food.
Now I know why MDF is denser then real wood.
Bill D.

[Jim Dwight]

Seems like another reason to avoid MDF. Besides the terrible dust.

Sorry you had this experience and thanks for the heads up.

[Andrew Hughes]

Glad I don’t have a sawstop.
When I get a good tablesaw blade I’m very careful how I treat it.

[Jerry Bruette]

Could you stick a magnet in the sawdust and see if any of it sticks, to verify if there's metal in the MDF?

[Alex Zeller]

I would try using a multimeter on the factory cut edge. Since you have a "bad" piece you could try both the resistance and capacitance settings to see what you get for a measurement. I'm assuming that you can't see shiny flakes of metal in the MDF. If you have a piece that you cut successfully you could see if you can measure a difference. It could be something like aluminum or so small that a magnet may not be useful.

[John Lanciani]

Seems like another reason to avoid MDF. Besides the terrible dust.

Sorry you had this experience and thanks for the heads up.

Seems like another reason to avoid SawStop...

[Frank Pratt]

Seems like another reason to avoid SawStop...

Please don't tell me we're going to resurrect that tired old rant again.

[Stan Calow]

Thanks for the warning.

[Larry Frank]

This is the first I have ever heard about MDF causing an issue. Thanks for the warning. Must be a lot of metal in it.

I would like to know if a metal detector goes off with it.

If you touch the blade to the MDF with the saw off, do you get a red light?

RANT..I get so tired of the Sawstop arguments. It is so simple. If you want one, then buy one. If you do not like them, don't buy one.

[Andy Pedler]

Unrelated to the MDF issue, but last weekend my Sawstop brake tripped for no apparent reason (the blade wasn't even spinning...it tripped when I pulled the paddle switch). Called Sawstop on Monday and without going into too many details, they went above and beyond to make sure I was back up and running. My saw is more than a decade out of warranty but they treated me like I was a brand new customer. It was my first experience with their customer support and it was outstanding.

[Ray Newman]

"The SawStop rep said that some factories use the cheapest filler that they can get. He mentioned that the products that they have been able to trace have been made offshore."
--BobMcBreen

BINGO! Back in late January/early February 2020 I bought an unmarked as to manufacturer 3/4"x4'x8' sheet of "shop grade" plywood at Home Depot to build some shop storage boxes and a small cart for The Squeeze to move one her sewing machines around. Ripping it all to size, I noticed a great deal of voids, then on one of the scrap pieces I noticed what appeared to be string hanging out. Pulled on it and about two feet of a Nylon type cord came out along with a poorly fitting plug to fill a large void.

[Bob McBreen]

I just received my replacement brake cartridges & did a test cut of the suspect MDF in by-pass mode without dust collector turned on. When running a rare earth magnet through the dust some of the particles stuck to the magnet. Pretty clear that the tech at SawStop was correct about metal in the MDF.

I next ran some other MDF through the saw & the magnet didn't collect any particles. Now time to clean my shop...

[Rod Wolfy]

Thanks for the heads up!

Makes me wonder if they're not using leftover shavings from metal fabricators in China or the like? I'd bet that metal shops have lots of leftover metal dust, kind of like woodshops. Now there's a market for it?

[Larry Frank]

Thanks for the information. If you have a metal detector, please run it over the mdf.

[Rod Sheridan]

I'd be interested to see if anyone has an insulation resistance meter (Megger) and could check the resistance of the MDF at 250 or 500 volts?

Regards, Rod.

[Frank Pratt]

I'd be interested to see if anyone has an insulation resistance meter (Megger) and could check the resistance of the MDF at 250 or 500 volts?

Regards, Rod.

I've got a Fluke high voltage insulation tester that has 500V & 1000V scales and will try it out on what MDF I have on hand. I've not had a trip on the MDF I've cut, but the results will be interesting.

Thanks for giving me the idea. Next time I buy MDF, that tester is going to the lumber yard with me.

[Thomas Wilson]

If I were a conspiracy theorist, I would take note of the fact that Sawstops are made in Taiwan and the Mdf was made in China. But I’m not.

[Thomas Pender]

Not sure I would ever choose to cut MDF on my Sawstop, but this particular thread is why the Creek is an invaluable resource. (Is also tough on the good blades we tend to have on these saws.). I think we all would agree that cutting MDF is an unpleasant experience (dust alone), but whoever would have thought it would be expensive? Took one of my rare earth magnets to some exposed MDF I bought from a big box to mount my Kreg jig on - no pull. However, some crummy MDF stuff that came packing something I bought seemed to have some pull. Interesting - the way Dr. Gass explained it to me under oath, is that it is the electrical potential of our bodies that pops the safety device. Guess it means crummy MDF also has electrical potential as does some pressure treated stuff. Again, thank you for starting this thread.

[Thomas Wilson]

Not sure I would ever choose to cut MDF on my Sawstop, but this particular thread is why the Creek is an invaluable resource. (Is also tough on the good blades we tend to have on these saws.). I think we all would agree that cutting MDF is an unpleasant experience (dust alone), but whoever would have thought it would be expensive? Took one of my rare earth magnets to some exposed MDF I bought from a big box to mount my Kreg jig on - no pull. However, some crummy MDF stuff that came packing something I bought seemed to have some pull. Interesting - the way Dr. Gass explained it to me under oath, is that it is the electrical potential of our bodies that pops the safety device. Guess it means crummy MDF also has electrical potential as does some pressure treated stuff. Again, thank you for starting this thread.
I would guess you are Thomas B. Pender. Saw Mill Creek has a diverse and interesting membership.

[Mark Blatter]

Unrelated to the MDF issue, but last weekend my Sawstop brake tripped for no apparent reason (the blade wasn't even spinning...it tripped when I pulled the paddle switch). Called Sawstop on Monday and without going into too many details, they went above and beyond to make sure I was back up and running. My saw is more than a decade out of warranty but they treated me like I was a brand new customer. It was my first experience with their customer support and it was outstanding.


I had the same experience about six months ago. I had just put on my dado stack and turned on the saw. The blades had enough time to just start to turn when the cartridge triggered. The blades were embedded less than 1/16" into the stop portion. I sent the cartridge to Sawstop for them to read. Took about two weeks for them to get back to me (guessing the slowness was COVID related) and they said that the something was touching the blade to trigger it. Well, I explained not a chance and nothing was touching the blade. They sent me a new cartridge at no cost, but I learned a valuable lesson. Any time I change a blade or adjust anything, I visually check the light prior to turning on the saw.

Now about a month ago, I changed the expensive blade I normally run to an old one my wife bought at a garage sale. She got 8 blades for $20, and most were good to great quality blades that just needed sharpening. I put on one of the lower quality blades as I was going to cut an 8' stick of aluminum angle. Made sure it was set then started the saw, picked up the aluminum and 'POW' triggered the cartridge. In checking every out and being as safe as I could, I forgot to put the saw into bypass mode.

I now have the old cartridge with fully embedded blade hanging on the wall by the door to remind me not to be stupid again.