Kickback

[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.

[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.