Warned By the Table Saw!

[Donn]

I was trimming the long edges of some wood flooring strips, when the table saw reminded me push sticks are false safety items. The piece kicked back, slamming my end of the push stick into the inside of my right hand, between the palm and heel...forcefully. I've got an L-shaped gash there, and the hand still feels like it was stepped on by a Lippizaner.

So, I spent several hours researching table saw techniques, especially for small piece work. The result of my reading was ordering a pair of these:



and one of these to use with them:



A broad consensus on several woodworking forums praises them highly.

Opinions?

I'm also considering the manufacturer's splitters...no decision yet.

[Rum_Pirate]

You need a SawStop


Long clip with a real finger

SawStop saws are equipped with a safety
system to stop the blade within 5 milliseconds of
detecting contact with skin. SawStop saws detect contact with skin.
The blade carries a small electrical signal, which the safety system continually monitors.

When skin contacts the blade, the signal changes because the human body is conductive.

The change to the signal activates the safety system.

A heavy-duty aluminum brake stops the blade.
The blade stops within milliseconds of detecting contact, quicker than a car airbag deploys.

During this time three things happen:

1.An aluminum brake springs into the spinning blade, to stop the blade.
2.The blades angular momentum drives the blade beneath the table, removing the risk of subsequent contact.
3.Power to the motor is shut off.
Resetting the saw is easy. It takes about five minutes to replace the $69 single-use brake cartridge and blade.
SawStop® table saws are the most advanced saws in the world, setting the standard for table saw safety.
SawStop saws are equipped with a safety system that detects when someone accidentally contacts the spinning saw blade, and then stops the blade in milliseconds. In most cases, such an accident would result in just a nick on a SawStop saw, instead of the devastating injury which would likely occur on an ordinary table saw.

The SawStop safety system includes an electronic detection system that detects when a person contacts the blade. The system induces an electrical signal onto the blade and then monitors that signal for changes. The human body has a relatively large inherent electrical capacitance and conductivity, which cause the signal to drop when a person contacts the blade. Wood has a relatively small inherent capacitance and conductivity and does not cause the signal to drop.

This drawing shows the changes in the electrical signal when a finger touched the teeth of a spinning saw blade during an actual test.

The line represents the electrical signal, which dropped quickly when the blade touched the finger. The dips in the signal line illustrate the changes in the electrical signal that were detected as two successive teeth touched the finger. When the detection system sees dips like these, it knows a person has touched the blade.

In order to stop the saw, a fast-acting brake stops the blade when contact is detected. The brake includes a heavy-duty spring to push a block of aluminum, called a brake pawl, into the teeth of the blade to stop the blade from spinning. The spring is held in compression by a fuse wire until contact is detected. When contact is detected, the system sends a surge of electricity through the fuse wire to burn the wire and release the spring. The spring pushes the brake pawl into the teeth of the spinning blade, and the teeth cut into the aluminum and bind, thereby stopping the blade. All this happens in about 35 milliseconds, or 1/200th of a second. At the same time, the angular momentum of the blade causes the blade to retract below the table and the power to the motor is shut off.

The brake mechanism is shown in the drawing to the right. The arrow shows how the aluminum brake pawl pivots into the teeth of the blade. The brake pawl is part of a replaceable cartridge that includes the spring, fuse wire and electronics necessary to burn the fuse wire. An optional dado cartridge provides the same protection for dado cuts.

The standard and dado brake cartridges are single-use components that must be changed if the brake is ever activated. Changing a brake cartridge is fast and easy, no more complicated than changing the blade.

[Rum_Pirate]

for a quick clip (with a sausage)

[John of Phoenix]

You'll find that working with small pieces is dangerous on any tool. It's easy to lose control of the stock.

Interesting gizmo you have there. I'll give it look.

Congrats on getting away relatively unscathed.

[Phillip Allen]

I don't think the saw stop actually addresses that situation

[Donn]

Sawstop doesn't prevent kickback.

JoP...have you shopped at Woodworker's Resource? I've bought some very nice wood from them recently.

[B_B]

...Congrats on getting away relatively unscathed.

Ditto on that.
I've always done it the way you did it - no troubles so far (knock wood). Slow and easy is my mantra when ripping, fully aware it doesn't help in every situation.

[Donn]

No, I wasn't using a featherboard. I was using two pushsticks...1 to advance the piece (24" long) and 1 to hold it against the fence. Featherboards are just as faulty a safety feature as pushsticks. They have to be positioned between the user and the blade, and once the piece passes the featherboard, they no longer work. Kickbacks happen at the back of the blade..several inches past the featherboard.

[Donn]

The tool is called Grr-Ripper. It's meant for ripping all lengths of wood, has been around for several years and won several awards for new woodworking tools. They're available pretty much everywhere. I ordered it from Hartville Tool.

Kickbacks are caused by more than the workpiece coming away from the fence, but a left-side featherboard won't hold it against the fence at the back of the blade. The Grr-ripper does.

[seanz]

Riving knife.

[John Meachen]

Good luck with the new gadgets.I would still advocate a crown guard and riving knife,they are a legal requirement for all businesses here and I can understand why.

[Nicholas Scheuer]

I make substantially the same thing using wood scrap & C-clamps. Of course thay're a lot cheaper, but have made nice odd-angle cuts on very small pieces.

My 10-in 2-hp doesn't take prisoners.

[Domesticated_Mr. Know It All]

Glad to hear you're new nickname ain't "Stubby"
I'll leave the good advise to the real know it all's.

[PeterSibley]

Install the riving knife then think about new gadgets .

[McMike]

I'm glad you didn't get hurt badly.

There are all kinds of techniques to cut small parts, you just learned one way not to do it. Those are the best kinds of lessons, ones you won't soon forget but don't scar you for life.

[John B]

No, I wasn't using a featherboard. I was using two pushsticks...1 to advance the piece (24" long) and 1 to hold it against the fence. Featherboards are just as faulty a safety feature as pushsticks. They have to be positioned between the user and the blade, and once the piece passes the featherboard, they no longer work. Kickbacks happen at the back of the blade..several inches past the featherboard.

Donn , its better to use the push stick just for pushing the job through, and a good wide piece off offcut, say some 3/4 or inch ply ( or whatever is appropriate for the thickness of the material you're cutting) or MDF to hold it into the fence. If its a couple of feet long and say 8 in or a foot wide then you have good safe control and your hands well away.

[McMike]

Oh yeah . . . also round off the sharp corners of your push sticks, they will turn into knives if pushed hard enough.

[Canoez]

Riving knife.

+1 on the Riving knife or a splitter on the saw insert. The Saw Stop has a Riving knife which would have helped avoid the situation, but if you have a kickback, the Saw Stop's function would not have helped a bit. Add your feather board gizmo after you put a splitter on and it will probably also be helpful.

[John B]

Thats not Donns saw so for all we know , he does have a riving knife.
Featherboards are all very nice if you're running a whole lot of stock down to another dimension. inch down to to 3.4 say, but I don't think I could be bothered re setting one each pass if you're ripping strips off a plank.

[Donn]

My saw has no riving knife, which is why I'm considering splitters for the ZCI. The same company, MicroJig, makes a few different ones, which pop on and off the saw in seconds.

[John B]

Interesting. I can't really think of many cuts that need the riving knife and guard removed off my saw, so I don't get why they're even sold without.
I'm uncomfortable about some aspects about that gripper push system but I guess that its an answer of sorts for an application. Personally , I would not be happy about my hand passing over the blade while pushing down, regardless of the clearance.

For interests sake Donn, what size are the strips you're ripping , and what size stock are they from. I ask because the smaller they get the more tricky it becomes ( for obvious reasons)

[Keith Wilson]

I prefer this push block design, but with a smaller nub hooking the end of the stock so the weight of your hand is farther forward. Easy to make out of scrap plywood, and reasonably safe with care.

[Donn]

John..my saw is a mid-50's Craftsman freebie, upgraded with new pullies, belt and Delta fence.

The pieces I was working on are ~4" x 24". Just a little too long for my sled. I was taking ~3/8 off one edge.

Check out the videos of the Grr-ripper on u-tube.

[Donn]

Keith..that design..the 'shoe,' gives you good forward control, some downward control, and little lateral control (holding the wood against the fence).

[Keith Wilson]

Pretty good downward control, but no lateral control at all, really. That's what the other hand is for, or a featherboard if the stock size is such you can't use your hand.

OTOH, that Microjig system probably works very well, but I prefer simplicity and visibility. (Link to their website.)

[John B]

I prefer this push block design, but with a smaller nub hooking the end of the stock so the weight of your hand is farther forward. Easy to make out of scrap plywood, and reasonably safe with care.

Thanks for the links.
I don't really like the look of that one either, your palm is a few inches away and pushing directly at the blade, and you can't use it on a guarded saw either.
I think that whenever you look at things like this you need to default to safe should it hit the fan. To my mind your push stick is longer than the blade diameter and keeps you well back behind the blade , not directly over it and you have 'lever' pressure down , not direct.

Since I do less on the floor and drive a chair more often, I have a mantra when I go to the saws or spindle moulder( shaper).

'You can't have me today you $%$# er.'

[GregH]

If your pushstick was able to put a gash in your hand, it was/is a poorly designed pushstick! It should be relatively slim, with well-rounded edges, and no abrupt changes in shape- it should be able to slide easily through your hand. I'll withhold my opinion on the Saw Stop.

[John of Phoenix]

JoP...have you shopped at Woodworker's Resource? I've bought some very nice wood from them recently.

I have a pretty good supply of hardwood right now so I haven't been there recently but it's a great store with very friendly and helpful people. I bought all the mahogany for both boats there and took pictures to the shop when finished. They got a big kick out of it all.

That MicroJig riving knife set up looks like it would solve your kickback problems. The video is a great demo of the Gripper too.

[JMAC]

It sounds like a routine cut that would have been better controlled with your hands. I use a pushstick for rips less than 3". I can't see any good reason to use 2 push sticks, there's not much control there. Did you have the driving pushstick in use before it got to the table? The kickback may have been caused by the wood leaving the surface of the table at the blade.

[David G]

Donn - You need to get your saw set up right, work on your technique, and figure out the practical physics involved. The gadgetry is maybe nice... but I've always found gadgetry to be more seductive than practical. Mostly it ends up gathering dust. If you use it religously... maybe it'll protect you (though not if your saw setup is flawed). But you'll end up with each cut being far more tedious than necessary, and therefore your incentive to either use the saw or use the gadget will decrease.

Glad to hear you weren't injured worse. The comments about the jagged push stick are correct. A decent push stick won't injure your hand, other than maybe a slight bruise, during a kickback. I favor a design much like what Keith pictured.

[Paul Girouard]

I was trimming the long edges of some wood flooring strips, when the table saw reminded me push sticks are false safety items.

Opinions?

So you where ripping , or cross cutting ??? WTH are long EDGES???

Almost always use a "close to" zero clearance insert , even when ripping stock . What it reads to me that you did was rip some short boards with a T&G edge and the tongue part rolled on you maybe , OR you where cross cutting with the rip fence. And the "nub" got hung up causing a kick back?? Which is closer to what you did?


I'm not a big fan of the Kieth Wilson style of P/S , here's a photo of the one I like to use :



Those have both been replaced with a similar new one. 3/4" ply generally Maple or shop Birch, 1/8' radius on the handle . Pretty upright design keeps your hand about 4" or more above the blade.

[Paul Girouard]

Also it looks like Mr. Wilson's P/S is lumber , I rarely use a lumber P/S maybe in a pinch on a job site , but I much rather have a plywood P/S , less likely to split , give you a splinter , etc.

[B_B]

So you where ripping , or cross cutting ??? WTH are long EDGES??? ...

Good lord Girouard - EVERYONE knows an "edge" is with the grain and an "end" is agin' it. Sheesh.

[Keith Wilson]

Also it looks like Mr. Wilson's P/S is lumber

Mine are plywood; that was just a picture I found to show the shape. I make them about 9" tall.

[MiddleAgesMan]

It sounds like a routine cut that would have been better controlled with your hands. I use a pushstick for rips less than 3". I can't see any good reason to use 2 push sticks, there's not much control there. Did you have the driving pushstick in use before it got to the table? The kickback may have been caused by the wood leaving the surface of the table at the blade.

Prezactly. I never heard of using two push sticks. Something about that bothered me from the start.

And with 4 inch wide boards you don't need any push sticks 'cause your fingers/hand can handle things just fine.

BTW--I don't use a push stick until the distance between the blade and the fence gets below an inch but I have small hands and thumbs. I know my thumb will clear the blade with an inch clearance as long as it's gliding along the face of the fence.

The only time I got cut in the shop was when I made a bad move with a pocket knife.

[John B]

So you where ripping , or cross cutting ??? WTH are long EDGES???

Almost always use a "close to" zero clearance insert , even when ripping stock . What it reads to me that you did was rip some short boards with a T&G edge and the tongue part rolled on you maybe , OR you where cross cutting with the rip fence. And the "nub" got hung up causing a kick back?? Which is closer to what you did?


I'm not a big fan of the Kieth Wilson style of P/S , here's a photo of the one I like to use :



Those have both been replaced with a similar new one. 3/4" ply generally Maple or shop Birch, 1/8' radius on the handle . Pretty upright design keeps your hand about 4" or more above the blade.

yip, thems the ones.

[Lew Barrett]

Got any toe out on your fence? Getting the fence set up correctly is another aid that costs nothing and can keep the cut from binding.

[Paul Girouard]

Good lord Girouard - EVERYONE knows an "edge" is with the grain and an "end" is agin' it. Sheesh.

Donn's post didn't read like he was ripping, so maybe it was the T&G that rolled on him. I don't think I'd use "long edges" , it was a confusing description / sentence to me. Maybe it was crystal to you , me , ah not so much. I mean how do you lose control of a rip unless it binds or rolls and a guy should expect that to happen if ripping a tongue edge so a good grip should be maintained!

[David G]

Got any toe out on your fence? Getting the fence set up correctly is another aid that costs nothing and can keep the cut from binding.

That's definitely a part of getting the saw set up correctly. You don't want much, but you want to shade that way, instead of shading toward toe-in... which creates a pinching effect, and encourages kickbacks.

The step-by-step on how to set up a saw is so readily available these days, that it's an easy first step - no matter if you're experiencing problems or not. Far more fundamentally sound than buying gadgets to try and compensate for your setup or your technique.

[John B]

That did occur to me. One of the golden rules of fencing of course , being that you lock off after adjusting in only. Adjust out and you'll pinch the exit on even the best of fences.

[Donn]

I have a ~.005" toe out on the fence. The blade is dead-on parallel to the miter channels, and perfectly perpendicular to the table.

I just got back from the clinic, where I was chastised for not coming in within 6 hours. I'll have to settle for healing by 'secondary intention,' as the wound can't be closed by suture, staple or butterfly. They trimmed away a bunch of ischemic tissue, and I have an open hole the size of a nickel in the middle of the inside of my hand. I'll be dressing it with antibiotic cream, taking a course of oral antibiotic for two weeks, and the wound will take at least two weeks of dressings to heal over...but I can use the hand gingerly. It looks like I have it taped for boxing, from my wrist to the base of my fingers, with two lengths of stretch/
ace bandage. Very awkward and clunky.

[Phillip Allen]

I have a ~.005" toe out on the fence. The blade is dead-on parallel to the miter channels, and perfectly perpendicular to the table.

I just got back from the clinic, where I was chastised for not coming in within 6 hours. I'll have to settle for healing by 'secondary intention,' as the wound can't be closed by suture, staple or butterfly. They trimmed away a bunch of ischemic tissue, and I have an open hole the size of a nickel in the middle of the inside of my hand. I'll be dressing it with antibiotic cream, taking a course of oral antibiotic for two weeks, and the wound will take at least two weeks of dressings to heal over...but I can use the hand gingerly. It looks like I have it taped for boxing, from my wrist to the base of my fingers, with two lengths of stretch/
ace bandage. Very awkward and clunky.

is this karma for cutting up the rosewood?

[David G]

Donn - sounds ugly. Hope you heal quickly and well!

Seems like you might have your saw setup dialed in sweetly. Next focus is technique.

[Donn]

is this karma for cutting up the rosewood?

It's hard to use it without cutting it.

Seems like you might have your saw setup dialed in sweetly. Next focus is technique.

That's what I'm doing every day. I'm making items of little consequence, in order to practice techniques.

I think the problem, this time, was not enough downward pressure on the end of the piece as it got to the back of the blade. The scar on the bottom indicates it tried to climb up and straight over the blade. The Grr-rippers should eliminate that issue.

[Paul Pless]

Donn, the single best thing I ever did with regards to the table saw, was to take a four hour introductory class at Woodcraft. I was loath to go until forced by Katherine to do so. But sitting in a room with five guys and watching each of them make various cuts and then be critiqued by the instructor was just what I needed. After that, bolting the damn thing to floor was then next best thing for both the quality of the work and the confidence I have in using the tool. Then push sticks of course - I use one that lefty suggested.

[Canoez]

I have a ~.005" toe out on the fence. The blade is dead-on parallel to the miter channels, and perfectly perpendicular to the table.

I just got back from the clinic, where I was chastised for not coming in within 6 hours. I'll have to settle for healing by 'secondary intention,' as the wound can't be closed by suture, staple or butterfly. They trimmed away a bunch of ischemic tissue, and I have an open hole the size of a nickel in the middle of the inside of my hand. I'll be dressing it with antibiotic cream, taking a course of oral antibiotic for two weeks, and the wound will take at least two weeks of dressings to heal over...but I can use the hand gingerly. It looks like I have it taped for boxing, from my wrist to the base of my fingers, with two lengths of stretch/
ace bandage. Very awkward and clunky.

Heal quickly and well.

[S/V Laura Ellen]

I had a look at the grippers and found them very fiddly. Anything that requires a lot of fiddling with will quickly become too much work to deal with, and if you decide not to bother, what will you be using then.

I've always just used feather boards and a simple push stick. The idea is to keep the board against the fence and the saw table and to keep your fingers out of harms way. Feather boards are quick and easy to set up and do the job very well.

This is just my opinion, your experience may be different.

[Jim Ledger]

I wouldn't bother with that contraption, Donn. You'll use it twice and then leave it on the shelf.

Push sticks are okay, I use them for very narrow rips, but they lack control. My usual method for close cuts is to ride my hand along the fence, three fingers behind the fence, pushing with the thumb and forefinger. My saw, however, is well-behaved and only kicks when the wood pinches together, maple is bad for that, but you just push it through and it burns a bit. The fence on my saw has zero toe, because a toed fence will produce out-of-square crosscuts. I don't have a feather board.

When you ripped the tongue off the board, was the tongue out, or against the fence? You should try to keep the largest piece of the board between the blade and fence. not always possible, but if you're ripping off tongue and grooves, that's the way to go.

[Donn]

I was trimming the outboard edge, away from the fence. This is engineered flooring, consisting of a hard wear layer, a fairly soft core, and a soft bottom layer. I wonder if the construction of the laminate creates internal stresses that interfere with the blade.

[David G]

I was trimming the outboard edge, away from the fence. This is engineered flooring, consisting of a hard wear layer, a fairly soft core, and a soft bottom layer. I wonder if the construction of the laminate creates internal stresses that interfere with the blade.

No.

But in re-reading, it sounds as if your setup might not be complete. It sounds as if you might be lacking sufficient outfeed support. A table or a roller stand.