[OP]
Member
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.
Last edited by Daniel Boddy; 04-14-2019 at 3:18 PM.
Contributor
Please post a picture of the blade tracks from the underside of the piece. That could be quite helful
[OP]
Member
I'm trying to figure out how to do that. New to forums.
Contributor
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.
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.Originally Posted by Daniel Boddy
"A hen is only an egg's way of making another egg".
– Samuel Butler
Contributor
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!
Ken
So much to learn, so little time.....
[OP]
Member
Contributor
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.
"Anything seems possible when you don't know what you're doing."
Contributor
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
Contributor
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
Contributor
Glad you’re okay - That’s a big chunk of wood to come flying at you!
Contributor
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"
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.
Lee Schierer
USNA '71
Go Navy!
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Contributor
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
Guest
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.
Last edited by robert wiggins; 04-15-2019 at 7:16 AM.
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