SawStop in the shop

[Chris Padilla]

Dave,

I wonder if the operators hand/finger was on the tape, too, or was touching the tablesaw top?

If I understand how this thing works, connecting the cast iron top to the blade shouldn't cause a trip because the device shouldn't see the unique human signal...unless some flesh was touching the tablesaw top or the tape.

[Allen Grimes]

Chris,

I dont think, it has anythng to do with a unique human signal. From what I understand is when electricity flows away from the blade it triggers the breaking mechanism (correct me if Im wrong anybody). Your flesh just the blade is electricly charged and your flesh sucks that electricity out. Im sure touching the blade to anything that is grounded would have the same effect without touching human flesh. I worded that very poorly but Im sure you guys get my point.

[John Shuk]

So what happens if you are standing on a non conductive strain releif pad whils cutting and no part of your body touches the saw body and your finger touches the blade. Does the brake engage? Lets take it further. What if you are cutting plastic and all of these other possible factors are in effect? I was under the impression that it somehow sensed a difference in density not electricity.

[Rich Konopka]

Dave:

Congratulations on receiving your SS. I hope you have more time over the Holidays to enjoy that fine piece of machinery. I'm curious in how many boxes it was shipped in and what kind of assembly was required.

Does the table and wings come separate?
at 600 LBS, can it be moved easily into a basement shop?
is there a mobile option?

Thanks for sharing the news !!

[Dave Wright #2]

Quotes from the Owner's Manual:

"When human skin comes into contact with the blade (or arbor), a portion of the signal is absorbed by the body due to the inherent electrical capacitance of the human body. As a result, the signal on the blade gets smaller and the detection unit recognizes this as contact."

"Conductive materials, such as aluminum and other metals...will ground the blade to the cast-iron table top, thus causing the signal on the blade to drop to zero and activating the brake."

It sounds to me like there are differences between the signal form resulting from body contact and table top grounding. The system is not 100% sure that it can tell the difference, and for sure it won't be able to sense body contact if its signal has been grounded, so the system defaults to the safety-oriented choice and releases the brake.

Edit: I just stepped out to the shop for a test. I turned the system on but left the motor off. Contact in this mode will result in the red LED flashing and the motor refusing to start up for five seconds. I touched the blade...flashing signal. I then held my electrician's pliers by the insulated handle, opened the jaws, and touched one tip to the blade and the other tip to the table top...same flashing signal.

[Allen Grimes]

Im not exactly sure how it works, John, and I can't answer any of your questions. What I said was just my impression of how it works. I really dont know anything about electricity.

[Dave Wright #2]

Hi John,

The system can be activated by being grounded, but all it really needs is to make single point contact with your blood stream. You could be suspended above the saw by insulating ropes and touch it with one finger tip and it would activate. People have asked "what if I'm wearing gloves". The answer is that the brake would not activate until it cut through both the glove and then your skin.

You have to receive an injury, albeit it a minor scratch, for the SawStop system to activate.

Regards,

Dave

[Dave Wright #2]

Rich,

The whole shebang came in 6 pieces. Yellow Freight brought 4: the saw (657 pounds gross weight including both cast iron extensions and miscellaneous hardware), fence, fence rails, and extension table. Fed-Ex brought 2: the first with the manual, cartridge, and keys; the second with spare cartridges and the dado insert I ordered.

Assembly was pretty easy. Bolting on the left cast iron extension, screwing in the speed handle to the tilt wheel, and connecting the power cord got the saw up and running. The fence rails bolted on easily. The extension table slipped into place and bolted right on too. I had to attach the extension brackets and leg. The zero clearance insert had to be set flush with the top. The fence had to be adjusted. I installed the blade, mounted the cartridge, and adjusted the blade/cartridge gap. I checked the blade alignment and found it to be spot on. That's pretty much it. If the 230v circuit had already been available, and if I was in a hurry, it might have taken me an hour or two.

The crux move on getting it into the basement would be getting the saw down the stairs. Fully crated it's essentially a 42" cube that weighs 657 pounds. Saw alone might weight 560ish and be a 34" cube. Its heavy...top heavy. We rigged it carefully, and only had to lift it up from a pickup bed and lower it to the shop floor, but there were a few tense moments.

A mobile base is not available from SawStop, and some have pointed out that the saw's shape (curved front) and great weight makes it tough to use one of the universal bases. I'm designing and building my own mobile base.

Hope This Helps,

Dave

[John Shuk]

Dave,
I wish you the best with your saw. I can't say the MAIN safety feature is a bad thing but I think the riving knife is not given enough attention here. That is a major improvement over what the American market is used to. I witnessed a kick back and an amputation both in one night. I bet both victims would have wished for this saw.

[Frank Pellow]

Dave,
I wish you the best with your saw. I can't say the MAIN safety feature is a bad thing but I think the riving knife is not given enough attention here. That is a major improvement over what the American market is used to. I witnessed a kick back and an amputation both in one night. I bet both victims would have wished for this saw.

I agree with you John that the the riving knife on the Saw Stop is a MUCH more important safety feature than the feature that the saw is synonymous with.

[Dave Wright #2]

John & Frank,

The riving knife is a key feature for me too. I haven't used other saws with riving knives, but this one seems like it's well engineered to me. Remove the insert, pull up a lever, and the knife comes right off if you want to switch it for the full guard. The knife and guard slip onto index pins and line up the same every time. The knife is substantial but will barely work with a TK blade.

I have never been cut by a moving sawblade, but have experienced several kickbacks and dozens of near-incidents. None have hit me yet (knock on wood). Hopefully the new saw will keep that record intact.

Dave

[Keith Christopher]

I remember reading about this device, it detects changes in electrical resistance as the blade passes between two sensors. Whent he threshold is met a quick blow fuse blows and it burns, a wire that is holding the spring loaded stop is then released and it jams into the blade.

[Tom Whalley]

May I also add my congratulations! I also have my hat in the delivery ring. I recently purchased a Vega fence for my current table saw. Would you recommend using that one on this saw, or ordering the optional fence? I am waiting for the contractor's saw. Looks like you have the cabinet saw in the picture, is that correct? I would like to learn more about this from the standpoint of one who has the saw. How does it know the difference between human and non-human as far as deploying the stopping mechanism? Are "false stops" a concern, and what is necessary to replace once the mechanism has been deployed? Is it costly to get the saw back in operation at that point?

Thanks for your responses!

[Dave Wright #2]

Tom,

Welcome to SMC from another newbie! The SawStop is up and running in my shop, and has been getting regular use. I now have it plumbed to a Jet dust collector. I really like it, but readers should know that I'm coming from a Delta Contractors Saw instead of another cabinet saw.

My general recommendation would be for a SawStop buyer to get the SawStop fence. It has a number of improvements to the strong Biesemeyer design, bolts right onto the saw, and, for what it's worth, matches the color scheme. I would qualify that recommendation, though, to say that you should first see if the SawStop Contractors Saw that you have on order can come with the same fence as the cabinet saw. There may be differences.

Yes, the saw I have is the cabinet saw - full name "SawStop 10" Professional Cabinet Saw". That's the only saw that they have released so far. I think the first contractors saws are to come out second quarter of 2005 or so. Delivery volume has been slow in ramping up. To get a realistic idea of your saw's delivery you would have to know your spot in line and add some fluff to the mid-2005 date.

The saw knows the difference between a human and wood because the two materials typically have different electrical properties. A small electrical current is placed on the turning blade. When that voltage dips in a characteristic way the saw knows that it has touched a human instead of wood, and deploys the brake.

False stops are a possibility, but SawStop has designed the saw to recognize and avoid some of them, and gives the operator the knowledge to avoid and work around the rest of them. False stops should extremely rarely, if ever, happen to reasonably smart woodworkers who have taken a little time to understand the machine.

Once the brake has deployed, you have to work the brake and ruined blade, that are now locked together, off their shafts. That can be tricky, but the Owners Manual includes a number of tips. They should know because they have tripped the brake intentionally over a thousand times. You then snap the rotating arbor block back up into position, install a new blade and brake cartridge, and get back to work. The cost of this process is your blade plus $59 and shipping for the cartridge. Some people have speculated that SawStop will make people cavalier and careless. I doubt that, seeing how each actuation is fairly costly.

Once they have final production versions of the contractors saw out there, I recommend that you figure out a way to visit one personally. It wasn't until that stage that I decided to go through with my cabinet saw order. In person, comparing the saw fairly closely to Unisaws and PM66s that were also at the show, I decided that it would be a good saw to own even without the blade brake. So far it's been delivering the sweet ride I had hoped. The contractors saw will be very different though. The cabinet saw was designed to be a "no holds barred" machine. It's an expensive saw, but they put a lot into it too. See if you can figure out what's taken out on the way to a saw that cost less than half as much.

Those were terse answers. Let me know if you want more detail on any of the topics.

Take Care,

Dave

[Alan Turner]

Dave,
Thanks for the updates. A question. Since metal will trip the stop, will cutting through a nail also trip the stop? I have been known to do that, although generally not on purpose.
Alan