How do I prevent dangerous kickback on a table saw?

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When cutting a board on the table saw the workpiece can sometimes be flung away from the saw at great (and dangerous) speeds.

What techniques or equipment can reduce the chances of kickback?

ratchet freak

Posted 2015-03-17T15:37:42.430

Reputation: 3 324

1In my middle school shop class, someone was ripping a piece of 2x4. The kickback shot it about 35' across the classroom area of the shop (where all the desks were) and left a huge dent in the chalkboard right behind the teacher's desk. Definitely an important issue! – FreeMan – 2015-03-17T20:23:44.880

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If you want a bragging contest about how bad of a kickback you witnessed please take it to chat.

– ratchet freak – 2015-03-17T20:25:50.097

I have been hit and cut by a 15" square piece of flying MDF, kicked back when it bound between fence and blade. Just missed my face. Important issue. – bib – 2015-03-17T16:26:00.773

Answers

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Riving knife! That's the best method. I've heard it said that it's impossible to have kickback with a riving knife.

enter image description here

(Image Source)

Other things to consider:

  1. Having a fence parallel to the blade. When it's not parallel, you might pinch the blade and cause the workpiece to fly back at you.
  2. Don't rip boards in half. If you have a six inch board that you cut in half, you're relieving a lot of tension in the wood and may get significant wood movement while cutting. Again, you might pinch the blade and get dangerous kickback. It's always better to rough cut on the bandsaw first.

Edit: One other thing to consider--I generally use two pushsticks like Mattias Wandel (https://www.youtube.com/watch?v=gdIQY_7T26k) so that keeps me on the side of the piece rather than behind it. That way, if kickback does happen, I'm out of harm's way.

Edit #2: I had to come back and add one more thing tangentially related to the OP. I read an article about someone using a sawstop who turned off the safety feature and lost his thumb. It looks like he was thinking about kickback (and using two pushsticks) and reached across the blade to free his workpiece. Bad idea.

dfife

Posted 2015-03-17T15:37:42.430

Reputation: 3 159

Your first auxiliary point is important to consider, as most saws have adjustments to keep the fence and the blade in proper alignment. Good point! – datUser – 2015-03-17T18:23:38.087

Came here to say riving knife. I have experienced kickback while using one, but it was my own stupidity. I hadn't bothered to raise the riving knife back up after performing a non-through cut. Luckily it was with a small square of plywood I was cutting, and it didn't have enough mass to do much damage when it hit me. I've never made that mistake again, and never experienced kickback again. – Doresoom – 2015-03-17T15:48:19.713

It only takes one time! I was cutting a drawer to fit without a riving knife. I tell you, a drawer has a LOT of mass! I slammed into my stomach and knocked the wind out of me. – dfife – 2015-03-17T15:51:15.463

Most kick back I've seen has to do with things getting trapped on an angle. I see some featherboards mentioned later. – NipFu – 2016-02-24T07:13:38.027

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Kickback can occur when the back of the blade gets pinched in the kerf, when a piece of wood is pinched between the blade and fence, or when a piece of wood is lifted off the table.

Anti-kickback equipment

As others have mentioned, a riving knife, anti-kickback pawls, and fence-mounted featherboards help protect against kickback.

If using a table-mounted featherboard, make sure it is positioned before the blade (infeed side). If you position the featherboard alongside the blade or after the blade, the featherboard will actually cause your wood to pinch the blade and cause kickback.

Other types of equipment include fence-mounted rollers and manual or automatic feeders.

Fence-mounted rollers are similar in function to fence-mounted featherboards but also help push the stock against the fence. The rollers are typically designed to only rotate in one direction.

Board Buddies fence-mounted rollers

Clear Cut stock guides

Manual feeder:

Duelen Safety Fence

Power Feeder:

Power Feeder

A splitter is not as good as a riving knife

If you have an older saw, you may have a splitter instead of a riving knife. Although a splitter and riving knife both prevent the blade from being pinched, a splitter is always positioned at the same height, while a riving knife raises and lowers with the blade. This allows the riving knife to maintain a constant distance from the back of the blade. This means that when the blade is lowered for a shallow cut, there is a huge gap between the back of the blade and the splitter, as illustrated in a kickback incident analyzed on LumberJocks. A splitter only performs as well as a riving knife when the blade is raised to full height--which itself is considered unsafe unless you need the full height of the blade to make a cut.

Crosscuts

There are some additional safety measures you can employ when making crosscuts.

Use a sled for crosscutting. The sled cradles your workpiece all the way through the blade and pushes both pieces past the blade after the cut.

Crosscut sled

Don't use your miter gauge and fence together. If you want to use the fence as a stop to cut off consistent lengths, clamp a piece of wood to the fence before the blade (on the infeed side). This way, the cutoff cannot be trapped between the blade and fence.

Think through the entire cut before you make it

Before you make any cut with any power tool, you should carefully think through the entire cut, from start to finish. Some of the concerns mentioned below can directly contribute to (or prevent) kickback, but all of them are important.

  • How will you push the entire length of the workpiece into, through, and past the blade?
  • Is there anything that could potentially block the path of the workpiece?
  • Where will each hand be through the entire operation?
  • What will happen to the offcut?
  • Will you be cutting through any knots or other unstable features?
  • What will happen when the workpiece is past the blade? Will it teeter on the back end of the saw (and possibly fall off)?
  • Do you need infeed or outfeed supports?
  • Where is the power switch, and how will you turn off the saw if the workpiece gets stuck and you cannot push it all the way through the blade? Can you turn it off with your knee so you don't have to move your hands?

Stand clear

Although it doesn't necessarily do anything to prevent kickback, you should always try to stand clear of the likely path of a kickback. In particular, stand off to the side of your workpiece if possible, and if you're using the fence do not stand in the zone between the blade and the fence.

rob

Posted 2015-03-17T15:37:42.430

Reputation: 15 938

Is a fence mounted roller (like the yellow ones in photo) available to buy? If so, where might I find one? thanks, R – None – 2015-06-05T21:11:11.860

@Randy The yellow ones pictured are called Board Buddies, and the black ones are sold as the JessEm Clear Cut TS. You can find these and maybe a few others by searching for "table saw roller guide" or "table saw stock guide." Most woodworking tool stores sell them. – rob – 2015-06-05T21:28:58.767

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As a secondary safety measure to @dfife's excellent riving knife suggestion, anti-kickback pawls are another option.

Generally they install on the riving knife itself, and are spring loaded to stay in contact with the workpiece. Think of it as a one-way clutch for your lumber.

Note that I've had issues with these scratching softwoods like pine, so I only use them if I'm still planning on heavy sanding or planing afterwards.

enter image description here

Image source

Doresoom

Posted 2015-03-17T15:37:42.430

Reputation: 3 118

8

It's not as effective as a the riving knife and and anti kickback pawls but a featherboard can help and it helps keep fingers safe.

enter image description here

bowlturner

Posted 2015-03-17T15:37:42.430

Reputation: 12 431

1The photo shows a router table rather than a table saw, but you are correct that a fence-mounted featherboard can help against kickback. If you use a table-mounted featherboard and you're making a through cut, be sure to position the featherboard before the blade (the infeed side). – rob – 2015-03-17T18:06:24.367

@rob yes I know it's a router, if I have time I'll find one with a table saw – bowlturner – 2015-03-17T18:07:45.620

Featherboards against fence (before the blade) and downward against the table can deff help on those hairy cutting operations. – datUser – 2015-03-17T18:17:45.097

5

Keep the larger piece between the blade and fence, and push on that with your push-stick. Most kick-backs I've seen were when a narrow piece was pinched between the blade and fence. And don't stand behind the piece!

Be extra careful twisted or knotted lumber that may have alot of internal tension - much more likely to pinch & kick back.

CoAstroGeek

Posted 2015-03-17T15:37:42.430

Reputation: 336

1this has been my experience as well. we call that area behind the piece "the line of fire". – NipFu – 2016-02-24T07:15:19.340