Gunshy

[Smythers]

Maybe someone has had a simillar expierence and can help me out. A few weeks ago I was at my table saw cutting a 2x4 into 4x4 squares. One of the squares kicked back and nailed me in my stomach after glancing off a finger. It hit so hard that it almost took my breath and left a nasty bruise, it also took a chunk of skinn of my knuckle and Im not 100% sure I didnt chip a bone. Yesterday I went back to the saw for the first time and only made 2 cuts before cutting it off. I was scared of more kickbacks. Any ideas on how to prevent kickbacks and get back on the saw?

[Sawduster]

You don't say how you were going about cutting the 2X4 into short sections. Hopefully you were not using the rip fence either with or without the miter gauge to make those cuts.

Generally kickback only occurs when using the rip fence, but it can happen if you try to bring the workpiece back to the operator side once you've made a cut using the miter gauge.

Installing a splitter on the saw helps immensely when doing rip cuts as it prevents the cut from closing up behind the blade and pinching the blade which can cause the piece to be thrown back at you. It also prevents the piece between the fence and blade from cocking into the blade and wedging between the blade and fence as the cut is completed.

Making use of anti-kickback pawls is helpful also.

Occassionally a piece cut using the miter gauge can cock over as the cut is completed and be caught by the blade and thrown back. An auxilliary fence attached to the miter gauge extending passed the blade and taller than the height of the blade is helpful in preventing small pieces from cocking into the blade. It also provides a zero clearence backing to the cut preventing tearout.

[Cody Colston]

You didn't say exactly what occurred to cause the kickback but chances are it was incorrect technique...using the rip fence in conjunction with the miter gauge, or trying to crosscut a piece that's longer than it is wide (a 2 x 4) using the rip fence is another.

If you are leery of the tablesaw, get a book on tablesaw use and learn proper technique and also where to position yourself. I've had loose cut-off pieces vibrate into the blade and get thrown. If you are in the line-of-fire, you're gonna get hit.

Cody

He is no fool who gives up what he cannot keep
for that which he cannot lose.

[Smythers]

I as using a miter guage on the left side of the blade and a fence on the right side set 4" from the blade.
What book would you reccomend?

[rhull]

Ditto on what Jerry and Cody have said.

One thing that I've found helps with tablesaw crosscutting is a sled. Instead of moving the piece into the blade, where the cut-off rests next to the blade (raising the possibility of it vibrating into the back of the blade and being picked up and thrown), you are instead moving the workpiece and the cutoff both past the blade. With the sled, after you complete the cut, you can safely move both pieces of wood out of the way before pulling the sled back past the blade.

[stretch2187]

Ditto on the crosscut sled, it's the best way to go.

The next best way is to clamp a scrap block of wood to the fence. Make sure that all of this block is is front of the blade. Allow for the width of the scrap when you set your fence. Using your miter guage, press the end of the board against the block and begin sliding it toward the blade. Make sure you hold the board tightly to your miter guage and that no part of the board you're cutting is touching the spacer block when the board touches the blade. Adding this spacer block prevents the board you're crosscutting from getting bound between the blade and the fence reducing the chances of kickback. However, you still need to stand out of the line of fire.

[beamerweb]

Aha!

That helps immensely.

There are a couple ways to perform the same operation while reducing the odds of being jolted into kickback territory. But first, I'll see if I can assume what went on with your technique:

You have a 2x4 on the miter guage. You want 4" long chunks of 2x4 so you move yer fence over to the 4" mark. Then you slide the 2x4 against the fence and run it through the blade. There was probably no problem with the first and maybe even the 2nd cut - they should just push themselves through the blade, right?

The trouble is when you get to the 2nd and subsequent cuts. The fence is trapping the offcut between it and the blade. Then when you come up behind it with another piece, if it isn't pushing the first offcut PERFECTLY straight, it'll cock the first piece just a little. There's very little room between the blade and the fence - especially when the piece is pushed back to the up-cutting teeth on the backside of the blade.

It only takes about one tenth the width of a frog's hair of twist to give those back teeth enough to grab onto. And WHAM! What happens next is hard to visualize, but i'll try to make a "Wurd Pitcher". That leading corner of the offcut just kisses a back tooth that lifts it just a smidge. Since it's just a little nib of the back corner, that lifting is also a tilting - raising that back corner a bit. Well there ain't no room for it to twist AND lean for sure. The tooth behind the one that got a small bite will get a bigger bit, accellerating the twist. It keeps doing this until the fence either moves, or the piece is lifted so high that the fence isn't a problem anymore. By then, you hear the sound WHAM!

The direction that little fiberous missile travels has a lot to do with how it came in contact with that first backside tooth. Many times, it'll just flip up and kick straight back. Other times, it'll get wedged by the fence and start to twist sideways and kick back toward the left of the blade. RIGHT AT YOU! (assuming you stand to the left of the blade, behind the miter guage. I do).

So now you know what might have happened. Here's what can be done to prevent it, in no particular order:

Offset fence stop. Take a piece of something. Anything that's at least 3/4" thick. About a foot or so long. Clamp it to the fence so that it stops about 3-4 inches AHEAD of the blade. Now all your fence settings need to be off by the thickness of that piece of something. A 1" thick something would do well here to keep the math easy. This solution is one of the easiest ones. But it ain't perfect. In fact, if you're crosscutting something longer than 2-3 inches and wider than 2-3 inches, it don't take a jeenyuss to know that the offcut could still get bound up between the blade and the fence if it twisted far enough.

Crosscut Sled. Two types are common - one that straddles the blade and one that just rides to one side of the blade. The one that straddles is arguably the safer of the two because the offcut doesn't have to "fall" a height equal to the thickness of the sled. During that fall, it could twist and ... powie.

And there i go again being wordy ... haha.

Jump back on that there horse, but first make sure yer saddle's tied on tight!

[Cody Colston]

Never, I repeat, never crosscut a piece using the miter gauge with the stock also riding against the rip fence. That is an open invitation to a kickback.

Now, I've heard many people recommend Jim Tolpin's "Table Saw Magic" as a good book for learning how to use the table saw. It will not only teach you about the dynamics of the saw but also many different cuts and techniques.

Cody

He is no fool who gives up what he cannot keep
for that which he cannot lose.

[beamerweb]

I'll echo that. I have it and it's probably the most complete book on the tablesaw i've seen. I have two others but i can't remember their titles....i never picked 'em up a second time, but Jim's i go back to quite a bit. :)

[TDHofstetter]

Always be aware aware of where your thumb is as you pluck that cutoff from the sled... be AWARE that if you thoughtlessly draw the sled back toward you to grab the cutoff, you run the risk of removing that thumb very nicely & painfully...!

-- Tim --

Work in the
SHOP
till you
DROP