Kickback

[Daniel Boddy]

I'm not sure what I did wrong here but boy did it hurt! I think I backed up a bit with the blade spinning. Also maybe because I was cutting so far from the fence. My first pass was good just not uniform in depth. About 2ft square 1/2" ply shooting back at me hitting me just above where it would have hurt a lot more. 3HP saw. Cutting 3/4 by 3/16 dadoes for dividers in a plane rack. Not real experienced with dadoes�� Pictures now posted below.

[Pat Barry]

Please post a picture of the blade tracks from the underside of the piece. That could be quite helful

[Daniel Boddy]

I'm trying to figure out how to do that. New to forums.

[Dan Friedrichs]

Glad you're OK - could have been much worse.

Even your brief post gives several clues to what could have caused this:

"backed up a bit with the blade spinning" - Every action should be deliberate, so why did you do that? Even so, backing up should not cause kickback unless you pulled the work out of line with where the blade had previously cut. So, overall, it sounds like you weren't controlling the workpiece well.

"cutting so far from the fence" - That shouldn't be a problem, unless you had inadequate support. Again, control of the workpiece. A narrow piece should be supported using a miter gauge, not the fence (if perhaps that's the problem you're alluding to).

"first pass was good just not uniform in depth" - That seems to imply that the workpiece is not flat, or your didn't hold uniform pressure on it. Either one could be disastrous.


Take some time to carefully consider the mechanics of how kickback occurs and how you can avoid it in the future. Watch some videos on the topic. Make sure your stock is well-prepared (flat, square, etc), your saw is in good alignment (blade parallel or slightly towed away from the rip fence), and in the future, try to stand to the left of the blade to avoid the highest-risk for kickback.

[glenn bradley]

I'm trying to figure out how to do that. New to forums.

First off, glad you're OK. Folks who haven't experienced the suddenness of a kickback launch have a hard time getting the idea of what it is like to be involved.

[Ken Fitzgerald]

I had been the proud owner of a table saw and DIYer for several decades before I witnessed an "attempted kickback" while ripping some white oak. The good news is the anti-kickback teeth on my blade guard and splitter worked well but it was amazing to see the tension in that oak attempt to reclose the gap in the wood!

Glad you weren't injured!

[Daniel Boddy]

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[andy bessette]

Exceedingly poor technique! You want the dado cuts to be close to the fence, not at the far side of the workpiece. And you never backup or feed toward yourself.

[Bernie Kopfer]

In order for kickback to have occurred in this setup the work piece has to have become twisted to the line of cut that the dado blades made. This allowed the blades to lift the wood out of the dado and catch the uncut surface and throw it at you. Extreme downward pressure over the blade would help but its you vs 3 horsepower. Just be smart and don't do it again. Making your cuts close to the fence is very important! If the wood binds and twists you now know what will happen! Don't hesitate to wax the tabletop and fence to minimize binding v

[Bill Dufour]

If you afraid to push down over the blade use a push block that looks like a wood plane. My bet is you did not push the wood down over the blade since you paid more attention to the fence side.
Bill D

[Matt Day]

Glad you’re okay - That’s a big chunk of wood to come flying at you!

[Mel Fulks]

If you backed up , the material must have stopped. That means the blade can heat up a bit. That can pinch and cause
kick back. "Be sure you are right.Then go ahead"

[Lee Schierer]

Also maybe because I was cutting so far from the fence. My first pass was good just not uniform in depth.

First, I'm glad you weren't seriously injured.

Second, From your own words the piece was cupped and you were getting uneven depth of cut. You can always make a second pass to clean up the depth, backing up is never an option with the blade spinning. You either pressed uncut wood down into the spinning blade or got the cut misaligned, which caused your kickback. Always try to stand out of the line of fire when you can.

Third, if your throat plate, which is missing in your first photo, was missing during the cutting operation that is dangerous. Having that much opening around the blade is unsafe. Buy or make a throat plate for your saw. A zero clearance insert will make for cleaner tear out free cuts.

Finally, use a push block to hold the plywood flat against the table while making any cut. Cuts where the blade is not coming up through the material are inherently more dangerous than other cuts. As others have mentioned, making cuts closer to the fence are safer.

[Derek Cohen]

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Making the cut so far out from the fence allowed the board to twist slightly. The twist caused the board to touch the back of the blade. Instant kickback! That is why we use a riving knife. Sawing close to the fence also reduces twist.

Regards from Perth

Derek

[robert wiggins]

The perfect operation for a feather board. In this instance cutting dadoes, 2 feather boards, 1 fore and 1 aft. A feather board would not only have held the material against the fence but would have also prevented any reverse feeding you thought you may have done. The piece was allowed to move away from the fence. This is where a big saw table is more difficult to control and maintain wood contact against the fence as it travels farther from the operator unless you're about 6'-12" tall.

[mat price]

First glad you are OK. Second thank you for posting this. It really helps people like me new to woodworking avoid incidents and learn. This is the very reason I prefer to use a router table or straight edge and router to cut rabbets and dados. Those blade just scare the hell out of me for some reason. So in this case should he have flipped the board so the two cut where at the fence side

[Daniel Boddy]

Thanks for all of your suggestions, they make sense. I repeated the job with a new piece of plywood and cut dadoes about every 3" successfully. And no, I did not stand directly behind the board! I do need to make some zero clearance plates.

[Ken Fitzgerald]

Daniel, thanks for reporting what happened to you. It's a valuable reminder to all of us to think about what we do daily to prevent serious accidents!

[Pat Barry]

I'm not sure what I did wrong here but boy did it hurt! I think I backed up a bit with the blade spinning. Also maybe because I was cutting so far from the fence. My first pass was good just not uniform in depth. About 2ft square 1/2" ply shooting back at me hitting me just above where it would have hurt a lot more. 3HP saw. Cutting 3/4 by 3/16 dadoes for dividers in a plane rack. Not real experienced with dadoes�� Pictures now posted below.

Were you trying to make a stopped dado on this cut? Looks like you targeted stopping just past the cross dado so as not to break out through the end. Regardless, pulling backward and getting a tad bit of drift off the fence, was likely the cause. Best practice would be to shut off the saw and wait for the blade to cease rotation at the completion of each cut. This is a good reminder for us all. I think your wood fence may have contributed also as the frictional drag would have been high enough to create a sticking point on the backward motion.

[Robert Engel]

Daniel,

Sounds like you got it. You either cocked the material or didn't lift it up high enough and the blade caught it.

Yes shallow dados are one operation where you really need to be on your toes. Repetitive cuts is the one thing that leads to errors because we get a bit brain lazy.

The problem with a cut like this is you can't use a splitter. Feather boards can help, but it can be difficult to use past the blade.

Keep in mind a router can do a good job of this, too and is a lot safer.

[Nick Shattuck]

The perfect operation for a feather board. In this instance cutting dadoes, 2 feather boards, 1 fore and 1 aft. A feather board would not only have held the material against the fence but would have also prevented any reverse feeding you thought you may have done. The piece was allowed to move away from the fence. This is where a big saw table is more difficult to control and maintain wood contact against the fence as it travels farther from the operator unless you're about 6'-12" tall.

1 aft? Like, pushing against part of the board that has been cut? That sounds really dangerous.

[Andrew Pitonyak]

I always have that board tight against the fence and pushing down. If you do a stopped cut, have your helper turn the saw off before lifting the board.

[robert wiggins]

1 aft? Like, pushing against part of the board that has been cut? That sounds really dangerous.
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Yes, and I see no danger unless the cut is a through cut. If a through cut then absolutely no aft.

[Nick Shattuck]

1 aft? Like, pushing against part of the board that has been cut? That sounds really dangerous.
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Yes, and I see no danger unless the cut is a through cut. If a through cut then absolutely no aft.

D'oh! I agree. I wasn't thinking about the dado cut for some reason even though it's the subject of this thread.

[Charles Lent]

If the board has any cup in it, the safest way to cut dados in it is NOT to use a table saw. A router will follow the cup. I'm assuming that you are going to pull this piece of plywood flat during assembly, but Using a flat board to begin with is the best way no matter how you do it..

Charley

[robert wiggins]

D'oh! I agree. I wasn't thinking about the dado cut for some reason even though it's the subject of this thread.

That's easily over looked so don't feel alone. If that's your first time, welcome to the group.:D

[Marshall Harrison]

Just glad that you didn't get seriously hurt. Lessons that we can learn from are the best kind.

[Frank Pratt]

As a standard practice, when I cut a dado, groove or rabbet on the table saw, I finish the job with a router plane. Perfectly even depth every time & it only takes seconds to do.

[Jeff Davies]

Hey Dan-- Yeah, that was fast, huh? Glad you only got a bruise. One of the problems with dado operations is they are only showing teeth...grabby teeth with no body or center field of blade like you would have in a regular blade through cut. in this scenario , once the work piece starts going backward, there is no stopping it . so, whether you meant to or not , any back feed will get away in a big hurry- particularly with smaller lighter pieces.
Like the other guys recommended, you need to shift to a router on this sort of thing. It will eliminate the inaccurate depth problem inherent to dado-tablesaw ops and make much cleaner cuts.
45 years ago, I used dado sets a LOT. About the time I bought a nice carbide dado set 35 years ago, I switched most all these operations to routers and never looked back --I could not tell you where that expensive dado set is now ,,I think I might have used it one time since then.
If you must use what you have , a second fence on the left could be clamped to the saw table . just crank the blade down and use your work piece as a gauge. that would prevent the piece from getting way out of hand , but won't make back feeding safe.
Regards, J J Davies

[Roger Feeley]

This thread made me think back to my days with the Kansas City Woodworkers Guild. They teach a table saw safety class there in which they force kickback situations using that pink foam insulation. I never did the class but I heard that it took a long time to get all the foam fragments cleaned up. I guess it was pretty spectacular.

[Jim Dwight]

I like dado blades for dados, I do not use one of my routers unless the workpiece is quite large. If you needed dados all along the workpiece, it is very handy to arrange the dados so you can cut from both sides. That keeps you from trying to cut a dado so far out from the fence. That doesn't work with a stopped dado. Any table saw cut where the width and length of the workpiece is similar is dangerous on the table saw. A dado goes from a dangerous to a normal type cut when you cut only the half of the workpiece closet to the rip fence (assuming a roughly square piece).

[Jacob Reverb]

This thread made me think back to my days with the Kansas City Woodworkers Guild. They teach a table saw safety class there in which they force kickback situations using that pink foam insulation. I never did the class but I heard that it took a long time to get all the foam fragments cleaned up. I guess it was pretty spectacular.

Can't remember where I saw it, but somewhere I saw pics of what happened when a guy was ripping long, skinny strips of wood on the TS and got a kickback. I guess the length of the strips gave the blade plenty of time to get the thrown workpiece up to speed, because when it kicked back, that skinny strip of wood launched out of the table saw and went THROUGH the tailgate of the pickup truck parked behind the saw!

I try never to stand behind the blade anymore after seeing that.

OP, glad you're OK, and thanks for posting up.

[Tom Bender]

If your push block is a 2 x 6 x 2" longer than the workpiece it can have a 2" wide strip of plywood glued to the bottom to push against the workpiece. This keeps your hands away, keeps pressure down over the blade and keeps the workpiece flat.

[Ben Rivel]

Glad this wasnt worse for you. This is one of the reasons I use my router with a guide rail adapter to cut dados whenever possible.

[David Less]

NEVER EVER STAND directly behind the table saw blade when making a cut!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!. Always stand off to one side. I see so much of this very bad practice.

The kick back is the TS killer not the finger in the blade mistake, well...that sucks too. Respect the machine and don't rush

[Karl Loeblein]

Daniel, Have you checked out unidirectional rollers guides to help prevent kickback and maintain even pressure against both the table and fence?


JessEm makes some really nice guides, but they're a bit expensive:
http://www.jessemdirect.com/product_p/04301.htm

Below some cheaper Guides & track from Woodstock:


Woodstock W1104 Board Buddies, Yellow
https://www.amazon.com/Woodstock-W1104-Board-Buddies-Yellow/dp/B0000223VK

Woodstock W1108 24-Inch Track for Board Buddies
https://www.amazon.com/Woodstock-W1108-24-Inch-Track-Buddies/dp/B0000223VG

[David Buchhauser]

Daniel, Have you checked out unidirectional rollers guides to help prevent kickback and maintain even pressure against both the table and fence?


JessEm makes some really nice guides, but they're a bit expensive:
http://www.jessemdirect.com/product_p/04301.htm

Below some cheaper Guides & track from Woodstock:


Woodstock W1104 Board Buddies, Yellow
https://www.amazon.com/Woodstock-W1104-Board-Buddies-Yellow/dp/B0000223VK

Woodstock W1108 24-Inch Track for Board Buddies
https://www.amazon.com/Woodstock-W1108-24-Inch-Track-Buddies/dp/B0000223VG

Karl,
I have a pair of the Yellow Board Buddies for one of my table saws - and they work great! An excellent safety product that also help to do better work by keeping the work piece against the fence as it is pushed thru the saw.
David

[Mark Klosky]

I am glad that the OP was not hurt to bad. I have a friend who ran his hand through a dado set, it was UGLY!

First off, you should never try to back a piece out of the spinning blades for a stopped cut, or in your case a stopped dado. Shut off the saw and wait for the blade to stop. A shop that I used to work in the owner would lift his sheet off the dado set for a stopped dado, but that didn't look real safe to me.

I heard you mention that your dado was not uniform in depth. the fix for this is easy. In fact this is how we did it in that same shop, and I still turn to this technique regularly in my shop. After roughing your dado on the saw you can chase it using a Whiteside 3000A or a 3000 bit in a small router. This will give you a uniform dado depth with a nice flat bottom. If you find yourself turning to this with any regularity then you might consider having a dedicated small router setup for this task.