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View Dautterguy's profile

OUCH what did I do Wrong?

by Dautterguy
posted 03-02-2008 04:38 PM


16 replies so far

View GaryK's profile

GaryK

10262 posts in 4549 days


#1 posted 03-02-2008 04:42 PM

Did you have the blade “just above” the height of the wood you were cutting?

-- Gary - Never pass up the opportunity to make a mistake look like you planned it that way - Tyler, TX

View gizmodyne's profile

gizmodyne

1784 posts in 4651 days


#2 posted 03-02-2008 04:43 PM

Start by checking the alignment of fence, blade, etc.

How long are the pieces?

-- -John "Do I have to keep typing a smiley? Just assume it's a joke."

View Dautterguy's profile

Dautterguy

51 posts in 4322 days


#3 posted 03-02-2008 04:45 PM

Sorry I faled to mention . The blade height gullet high. Just peeking over the height of the wood.

View GaryK's profile

GaryK

10262 posts in 4549 days


#4 posted 03-02-2008 05:02 PM

Start with what Gizmo suggested.

I like to raise the blade by about 1” higher than the wood. I feel that it less likely for the back side of the blade to pick up the piece and throw it back.

I wouldn’t think that fence alignment would be that much of an issue since it’s your fall off that’s
getting kicked back.

You could also try two push sticks.

-- Gary - Never pass up the opportunity to make a mistake look like you planned it that way - Tyler, TX

View Mark E.'s profile

Mark E.

387 posts in 4303 days


#5 posted 03-02-2008 05:07 PM

It could just be that the kerf is closing up behind the blade due to internal stresses in the wood.

Are you using a splitter/riving knife behind the blade?

-- Mark

View Dautterguy's profile

Dautterguy

51 posts in 4322 days


#6 posted 03-02-2008 05:08 PM

Thank You, At this point I am willing to try anything, I just cannot figure this one out. First time the fall off got me.

View CharlieM1958's profile

CharlieM1958

16284 posts in 4779 days


#7 posted 03-02-2008 05:17 PM

You give approximate dimensions of your cutoff, but which dimension is parallel to the blade? What I’m getting at is, is your cutoff small enough to fall partially between the blade and the table? This causes the effect youare describing, and is prevented by using a zero-clearance insert.

-- Charlie M. "Woodworking - patience = firewood"

View Peter Oxley's profile

Peter Oxley

1426 posts in 4435 days


#8 posted 03-02-2008 05:17 PM

This is kind-of a wild guess, but is there any chance your throat plate is lower than the table surface? With a short piece like you are cutting, if one edge was on the table surface and the other edge dropped onto a slightly lower throat-plate it would tip the drop toward the blade.

Taking the same theory one step farther, a zero clearance throat plate might help, and would probably be a good idea with pieces as short as you are cutting.

-- http://www.peteroxley.com/woodworking -- http://north40studios.etsy.com --

View Scott Bryan's profile

Scott Bryan

27250 posts in 4383 days


#9 posted 03-02-2008 05:39 PM

I agree wit Charlie and Peter’s assessment about the zero clearance insert. These are readily made or available commercially ($20). The only time I use my standard plate is when I am doing bevel operations.

-- Challenges are what make life interesting; overcoming them is what makes life meaningful- Joshua Marine

View Dick, & Barb Cain's profile

Dick, & Barb Cain

8693 posts in 4860 days


#10 posted 03-02-2008 06:57 PM

Back in the dark ages in 1947, when I first used a table saw, my instructor said run your saw blade about 1/8”

above the stock thickness you’re cutting. When I watch wood working shows, I never see this.

Also on a band saw, I always lower my guide down just above the wood. I kind of shudder when I see the experts

on TV, doing just the opposite. I think that’s why there’s a lot of bandsaw accidents.

-- -** You are never to old to set another goal or to dream a new dream ****************** Dick, & Barb Cain, Hibbing, MN. http://www.woodcarvingillustrated.com/gallery/member.php?uid=3627&protype=1

View USCJeff's profile

USCJeff

1065 posts in 4629 days


#11 posted 03-02-2008 07:02 PM

All good suggestions. I’d add a few more possible issues. It’s possible that the vibration from the saw makes the cutoff walk back to the blade. It could also be the wood itself. Changes in feed rate and the boards density could cause the board to “twist” as the blade cuts the last bit. The kerf closing as mentioned could do this too. Is there much runout with your blade? The blade wobbling (even slightly I would think) at high speeds could catch the cutoff.

Another solution is to use a sled of some sorts. A sled or long miter fence will push both pieces past the blade. They have their limitations though. Good luck. Stay safe.

-- Jeff, South Carolina

View Myron Wooley's profile

Myron Wooley

226 posts in 4457 days


#12 posted 03-02-2008 07:37 PM

Weird. I’ve never seen the offcut from a rip come back, but my son had a kickback that sounds similar. He was using the rip fence incorrectly to make a crosscut. He allowed his left hand to follow the offcut, and when the cut was complete, the back of the blade caught the piece between the fence and the blade and it went zinging back into his stomach. No hand injuries, but he was bruised pretty good. The board was only 1/4” thick.

Some questions to ponder:
In your case, was this a really a rip or should it have been treated as a crosscut?
Were you crosscutting using the rip fence?
Where was your left hand?
Were you making a crosscut with the miter gauge, using the fence as a stop, and pushing the offcut?
Did the offending piece come from the left or right side of the blade? Your description doesn’t say.

In order to generate the kind of force you experienced, the blade needs to work in conjunction with a fulcrum. Usually it’s the fence, but if the table insert is too low or the slot overly wide, it could catch. The dimensions you gave seem too large for this scenario, though.

Could you take some pics of the setup at the moment of the kickback? (please don’t turn on the saw!) Maybe we could get a better idea of what went wrong, and we can all benefit.

I’m glad you weren’t seriously injured.

-- The days are long and the years are short...

View Josh's profile

Josh

119 posts in 4499 days


#13 posted 03-02-2008 09:31 PM

Kick backs scare me. I watched a guy in high school take one to the dome and that left an impression.

I read that the blade is safest when it is just peaking over the piece you are cutting. I was wondering if the saw blade is more accurate the further it is raised?

I also try not to stand behind my cut. If you are getting hit in the stomac are you standing in the right spot when you are cutting? Should he of been standing further to the side when making this cut?

View Dautterguy's profile

Dautterguy

51 posts in 4322 days


#14 posted 03-03-2008 05:50 AM

Thank You All for the responses. I have been reading all of the posts everymorning. The responses were overwhelming.

View dlgWoodWork's profile

dlgWoodWork

160 posts in 4315 days


#15 posted 03-03-2008 06:10 AM

A lot of good responses have been mentioned already. I will add one more. You have your cutoffs listed as either 4 or 6 inches long. That is a pretty short piece of wood to try to be ripping, if that is what you are doing. I know from experience. I was ripping a piece of maple about 6 inches long once, once the end of the cut was made, the back of the piece climbed on top of the blade, then the blade threw it off my chin. Make sure if you are ripping stock, that the piece is long enough to pass the back of the blade when the cut is complete.

-- Check out my projects and videos http://dlgwoodwork.com

View Woodchuck1957's profile

Woodchuck1957

944 posts in 4325 days


#16 posted 03-03-2008 06:35 AM

I know one thing you were doing wrong, and it’s odd you didn’t correct it after the first time. Don’t stand in the path of the wood being fed. I allways stand to the left a bit, I’m right handed. Unless I’m there to see what your doing, I could guess all night.

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