Robert Morse

So this happened today... New SawStop.

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On 1/14/2019 at 8:31 AM, drzaius said:

You can test the brake function by touching the blade when the saw is not running. If you get a flashing red light, then it works. But, you say, 'I want to see if it actually works". Then you can do the wiener test, but then you have to replace the cartridge, & then how do you know that the new cartridge will work? Better to just not use the saw at all :) 

You also have to replace the saw blade, of course.

Plus the entire process is pretty jarring. A lot of force is required to stop the blade that quickly. Not the sort of thing I'd want to subject any machine to multiple times, if it can be avoided. 

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So if you're buying the floor model you might want to know how many hotdogs it's seen.

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46 minutes ago, Isaac said:

You also have to replace the saw blade, of course.

Yep, it may not look damaged but saving a little money versus getting hit by a loose carbide tooth is worth replacing the blade.

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19 hours ago, Mark J said:

So if you're buying the floor model you might want to know how many hotdogs it's seen.

Yeah. I mean if you watch closely on the demo videos, the entire saw jumps around. We all know these are big heavy machines, so that is a lot of energy.

19 hours ago, Chet said:

Yep, it may not look damaged but saving a little money versus getting hit by a loose carbide tooth is worth replacing the blade.

Actually the break pretty much destroys the blade, I think that is a guarantee. As far as I know, no one expects to re-use the break or blade after the mechanism goes off.  It looks like this,after all:

Image result for sawstop blade

Just to be clear here, I'm a Sawstop owner, so not trying to rip on them at all.

One thing I loved, that others have also mentioned, was just how clear the instructions were on setting up my jobsite saw. Big bright colorful pictures, and everything was very well packaged. A+ presentation. 

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@Isaac

+1 to @gee-dub

We did a hotdog demo in the store and then when my own saw tripped the brake, both times there's simply a pop and that's it. 

I've heard from ppl who have a SS in a school or work environment where the brake has been tripped multiple times and it's just fine. All the force is absorbed by the cartridge. It doesn't appear to have any negative effect on the rest of the saw at all. 

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22 minutes ago, applejackson said:

@Isaac

+1 to @gee-dub. 

We did a hotdog demo in the store and then when my own saw tripped the brake, both times there's simply a pop and that's it. 

I've heard from ppl who have a SS in a school or work environment where the brake has been tripped multiple times and it's just fine. All the force is absorbed by the cartridge. It doesn't appear to have any negative effect on the rest of the saw at all. 

Good to know. Personally, I will still do my best to keep trips to a minimum. :D

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1 hour ago, gee-dub said:

I have had two misfires on my PCS.  Both non-flesh boo-boo's by me.  If it wasn't for the dull "thunk" sound (and the fact that the material is no longer being cut :)) you wouldn't even know what happened when the safety system fires.  It is very anti-climactic; more a sense of confusion immediately followed by an internal groan than anything else.

I've done it once (cutting something conductive :( ) & that was my experience exactly. Suddenly the blade disappeared & all was quiet.

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38 minutes ago, Isaac said:

Good to know. Personally, I will still do my best to keep trips to a minimum. :D

I don't know if there are any aluminum parts inside the saw. The benefit on the cabinet style saws is they are made of cast iron so they won't fatigue well at least they won't as quickly as aluminum. I agree though there are a lot of forces at play here and I'd be hesitant if the mechanism was activated frequently. It has to have a life span of some sort. It's honestly difficult to find pictures of what the insides of the saws look like and how that whole thing works. I've always been curious what the device looks like that absorbs all that energy.

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@Chestnut

I am no engineer, but I will take a shot at explaining it the best I can.

The aluminum cartridge clamps onto the blade. The force of the spinning blade gets absorbed by the cartridge mainly in the area circled in red. The cartridge mounts on steel studs in the machine. I am sure there is some of the force that goes into the machine, but I believe that the vast majority of it goes into the cartridge. 

Here is a video that shows it in slo mo:

 

 

 

 

 

SS_Cartridge.jpg

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I suspect the largest impact/damage of a misfire is to your wallet.  :)

AppleJ - i think a part you're missing is that the entire blade-carrying assembly (pulleys, arbor, raise/lower mechanism, etc) is also designed to 'soften' the blow of all that rotational energy by dropping below the table.  This somehow transfers it into a more manageable form, rather than all that energy being absorbed by the deformation of the aluminum brake pawl.  I'm sure the cartridge absorbs a lot, but there's more than just the cartridge.

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So that is 1 force than the is the blade mechanism that shoots down into the saw. What stops that? How is the blade lifting mechanism connected and disconnected? Arbor bearings aren't expensive so I'm not really concerned about them but repeated fires will probably wear those out as the blade stopping is going to put some good force there as well. I'm more worried about parts that will fatigue with repeated impact strikes. Force doesn't go 1 direction remember newtons laws.

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51 minutes ago, Chestnut said:

So that is 1 force than the is the blade mechanism that shoots down into the saw. What stops that? How is the blade lifting mechanism connected and disconnected? Arbor bearings aren't expensive so I'm not really concerned about them but repeated fires will probably wear those out as the blade stopping is going to put some good force there as well. I'm more worried about parts that will fatigue with repeated impact strikes. Force doesn't go 1 direction remember newtons laws.

Would also love to find out more about this. I'd also be interested in info on how close the conductivity of a finger actually compares to that of a hotdog. Has anyone done the demo with a pig leg or something that is likely more similar to a finger? I've seen a few pictures that people have posted after their finger made contact with the blade, and while still far from severe, they do look worse than what the hotdog test suggests would happen. I know there's the video of the guy putting his finger into the blade for a demo, but it is not at all a real-world scenario.

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2 hours ago, JohnG said:

Would also love to find out more about this. I'd also be interested in info on how close the conductivity of a finger actually compares to that of a hotdog. Has anyone done the demo with a pig leg or something that is likely more similar to a finger? I've seen a few pictures that people have posted after their finger made contact with the blade, and while still far from severe, they do look worse than what the hotdog test suggests would happen. I know there's the video of the guy putting his finger into the blade for a demo, but it is not at all a real-world scenario.

Gass has done it with his own finger as well as countless people that have reported their near misses. The blades are still sharp and the scratch is still far better than the alternative.

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5 hours ago, Jfitz said:

This somehow transfers it into a more manageable form, rather than all that energy being absorbed by the deformation of the aluminum brake pawl.  I'm sure the cartridge absorbs a lot, but there's more than just the cartridge.

Only had the experience of the 1 brake actuation, but I gotta say that the cartridge has got to be taking the vast majority of the kinetic energy. The saw didn't move a bit. A light smack to the table with a rubber mallet is more of an event.

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I've seen high speed video of a cartridge firing. The blade came to an immediate halt, so quickly that it flexed and wobbled. The retraction happened a few milliseconds later. Looks kind of eerie in slo-mo.

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5 minutes ago, drzaius said:

Only had the experience of the 1 brake actuation, but I gotta say that the cartridge has got to be taking the vast majority of the kinetic energy. The saw didn't move a bit. A light smack to the table with a rubber mallet is more of an event.

interesting.  so maybe the drop-down is just to get the blade out of the way?  I've managed to avoid activating the brake, so other than seeing a demo of it once I've never really 'experienced' it.

 

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3 minutes ago, Jfitz said:

interesting.  so maybe the drop-down is just to get the blade out of the way?  I've managed to avoid activating the brake, so other than seeing a demo of it once I've never really 'experienced' it.

 

It seems to be a belt & suspenders approach. If a heavy blade doesn't slow down fast enough, then let's get it out of the way as well.

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25 minutes ago, drzaius said:

It seems to be a belt & suspenders approach. If a heavy blade doesn't slow down fast enough, then let's get it out of the way as well.

I'd be willing to bet a lot of money the blade retraction was a solution to a problem that they spun as a marketing advantage. All that momentum needs to go somewhere if you have say 200 lbs pushing up on the brake there is 200 lbs pushing down on the arbor. To make a mechanism that would be able to withstand that was probably to expensive and complicated so they diverted that energy down to dampen it another way.

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So quick update on the set up, specifically with comparisons to the PM2000.  

I cleaned off the oil tonight, using citrus degreaser, followed by a coat of CRC 3-36 and then paste wax.  I also got the hand wheels installed for blade tilt and blade height. Finally, I installed the blade. 

A couple of thoughts...

First, the oil/grease was more liquid like than the other tools I've set up. I ended up with drops of oil/grease all over the floor, and it was almost oozing out of the miter slots and around the blade opening. I think I prefer the greasier stuff I've seen on the other tools, as it cleans up easier. 

Second, it seemed like it was MUCH easier to install the blade into the saw - my somewhat large hands had no issues getting the arbor nut/flange on and off.  Even though the opening on the Powermatic is about the same size, it felt easier to get into the opening and get stuff done. 

The hand wheels went on with no problems at all, however, I'm missing one of the two locking screws to keep them in their set positions. I'll have to reach out to SawStop in the morning on that. 

By the time I was done with cleaning up and installing the blade, the kids were home from piano lessons, and it was time for dinner.  I managed to locate my dial indicator and a spare miter bar tonight, so I'll run it along the miter slots tomorrow to see how much adjustment is needed, if any. Then I'll get a strong friend or 2 over to help lift it into the mobile base. Pictures tomorrow for those interested. 

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@Robert Morse regarding your missing part, are you assembling in the order described in the manual or are you skipping around? I ask this because when I strayed from the steps in the manual, I thought I was missing a part too (can't remember which one specifically) only to find it later, packed in with some other parts). So there might be chance that your missing part is in there somewhere. And no offense meant. You night have unpacked everything and it really is missing. Definitely possible!

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12 hours ago, Robert Morse said:

Then I'll get a strong friend or 2 over to help lift it into the mobile base. Pictures tomorrow for those interested.

If you follow the manual, there is an order to the uncrating process that makes it super easy to put the saw on the mobile base. No straining needed.

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