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Anti kick back device for table saws

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Forum topic by MrRon posted 177 days ago 1188 views 1 time favorited 14 replies Add to Favorites Watch
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MrRon

2702 posts in 1828 days


177 days ago

Topic tags/keywords: tip

I’m surprised no one has mounted an anti kick back device on their fence for ripping. Ripping is when kick back happens. Radial arm saws have an anti kick back device that is a toothed crescent of metal on the end of a rod placed at the outfeed end of the saw carriage. The teeth glide across the wood as you push the wood through the blade. The metal crescent digs into the wood when the blade wants to kick back. It would be pretty easy to devise a similar setup for table saws. This would be quite effective when ripping narrow strips.


14 replies so far

View LeChuck's profile

LeChuck

417 posts in 1647 days


#1 posted 177 days ago

Most recent table saws, and not so recent, have anti kickback pawls. Good safety device. Unfortunately on my saw, they leave a mark that is a real pain to sand off (since it’s dug in), and that’s not always very visible until you put some finish on it, even after sanding. I wonder if I should take a file to the bottom of the pawls to make them less sharp.

-- David - Tucson, AZ

View PurpLev's profile

PurpLev

8475 posts in 2233 days


#2 posted 177 days ago

anti kick-back pawls have been on tables saws for AGES… since the days of the splitter/blade guard and before the inclusion of riving knives.

it is exactly what you described:

-- ㊍ When in doubt - There is no doubt - Go the safer route.

View pintodeluxe's profile

pintodeluxe

3214 posts in 1398 days


#3 posted 177 days ago

Featherboards and Board Buddy rollers are other options instead of the kickback pawls. They will not mar your workpiece.

-- Willie, Washington "If You Choose Not To Decide, You Still Have Made a Choice" - Rush

View CharlesA's profile

CharlesA

1007 posts in 382 days


#4 posted 177 days ago

or you can spend $75 on these:

View CharlesA's profile

CharlesA

1007 posts in 382 days


#5 posted 177 days ago

willie beat me to it.

View basswood's profile

basswood

255 posts in 205 days


#6 posted 177 days ago

I use both fence and table mounted feather boards that both hold stock tight to the table and fence.

These both improve rip quality and reduce the likelihood of kick back.

Also friendlier to the wood than aggressive pawls.

-- http://www.basswoodmodular.com/Tri-Horse-Builder-Plans-p/thbp.htm

View Bill White's profile

Bill White

3320 posts in 2545 days


#7 posted 177 days ago

I use pawls and Board Buddies when the work will allow. I’m a weenie when it comes to kick back.
Bill

-- bill@magraphics.us

View Nicholas Hall's profile

Nicholas Hall

339 posts in 691 days


#8 posted 176 days ago

I’ve never seen board buddies before. That’s pretty slick.

It doesn’t seem as though they would be very effective on narrow cuts. It looks like the narrowest cut they could make is about 2.5”. Is that the case, or is a way to set them up for narrower cuts? If so, how narrow can they go?

It does seem like a fence mounted cam style pawl would be able provide antikickback in narrower stock, for example when you’re cutting 1” spindles for craftsman style furniture. Does such a thing exist?

-- Outside of a dog, a book is a man's best friend. Inside of a dog, it's too dark to read. -Groucho Marx

View CessnaPilotBarry's profile

CessnaPilotBarry

876 posts in 695 days


#9 posted 175 days ago

I’m good with a properly installed riving knife, and properly face and edge jointed stock.

Pawls and Board Buddies annoy me, and in my opinion, don’t add anything to a properly installed knife. If the kerf can’t close, and the stock can’t get pushed against rising teeth, the board can’t kick back. If your blade is raised at least to the bottom of the gullets, and the knife is close to the back (rising) teeth, there is no way for a board to climb on top of the blade.

Setting a blade too low can create a kickback situation, even with safety measures installed.

On my previous saw, I used to install white oak splitters to my zero clearance inserts, less than 1/4” behind the blade. I kept inserts handy that matched a bunch of blade heights. The planed to match blade thickness splitter grain was oriented vertically, securely glued in place, and the leading edge was rounded and waxed. It was a shop-made version of the Micro Jig splitter, but it could be installed much closer to the blade, built to varying heights, and it couldn’t unintentionally come out. They worked great, unless the blade was tilted…

To me, the real riving knife made a bunch of stuff invented before it’s introduction obsolete.

-- It's all good, if it's wood...

View Nicholas Hall's profile

Nicholas Hall

339 posts in 691 days


#10 posted 175 days ago

I imagine there are a lot of us out there that would love to have a real riving knife!

Unfortunately, it seems like they have really only been available (except for an infinitesimal minority) in US for the past 5 years or so. Even now, I would guess that less than 1% of saws owned by Lumberjocks have a real riving knife.

The Grizzly 1023 that I work on doesn’t have one, but wired for 220V, it does have an enormous amount of power. As a result, I’m always keen to learn what other folks do to minimize the risk of kick-back. Pawls and board buddies may be a pain, but their not nearly as painful as fingers in a 20 tooth rip-cut blade at 8000 rpm!

CessnaPilotBarry: Your point about properly face and edge jointed stock is well taken, I’ve seen people try to “square the edge” of a wany edged rough cut board on a tablesaw in order to “save the jointer blades”. All the equipment in the world is worthless if you don’t at least square the edge on the jointer. It’s the kind of shortcut that can lead to long recovery times and physical therapy. I think that there are a lot of folks that make the transition to rough cut lumber that don’t understand that the jointer is one of the best pieces of safety equipment in the shop.

-- Outside of a dog, a book is a man's best friend. Inside of a dog, it's too dark to read. -Groucho Marx

View Eugene's profile

Eugene

13 posts in 471 days


#11 posted 175 days ago

This side of the pond, all table saws have an anti kick back device fitted, it’s a riving knife.
So called ‘kickback’ is caused when the timber pinches onto the rising teeth of the blade, a riving knife prevents this and kickback cannot happen.
We see all sorts of video’s on youtube of you guys using your table saws without riving knives and wonder how the heck you get away with it, obviously some don’t.
Have a look at this.
http://www.dailymotion.com/video/x7d2vt_kelly-mehler-table-saw_lifestyle

View nwbusa's profile

nwbusa

1016 posts in 871 days


#12 posted 175 days ago

I agree with Barry and also with the video link posted above. I personally wouldn’t use a table saw without a riving knife, although I don’t have much use for the blade guard and zero use for the pawls.

-- John, BC, Canada

View Nicholas Hall's profile

Nicholas Hall

339 posts in 691 days


#13 posted 175 days ago

Great video Eugene. That was time well spent. Kelly Mehler is a man who knows a thing or two about woodworking. It was pretty amazing to see his demonstration with the piece of styrofoam showing exactly how kick-back occurs.

If anyone has never seen kick-back in real life, you can see it up close and personal on a square of styrofoam at 11:55 seconds into the video. Even with a styrofoam “board” it’s pretty amazing to watch. The destructive force that it generates is incredible. I guarantee it you’ll work safer after seeing it in real life.

Thanks again for posting. I’ll be buying a micro-jig splitter before I fire up my saw again. Now I’ve just got to figure out where to get the money for a saw with a riving knife :)

-- Outside of a dog, a book is a man's best friend. Inside of a dog, it's too dark to read. -Groucho Marx

View CessnaPilotBarry's profile

CessnaPilotBarry

876 posts in 695 days


#14 posted 173 days ago

One more thing…

People who use Board Buddies, without a splitter or riving knife, on a higher horsepower saw need to be aware that a pinched blade due to reaction wood may generate enough force to lift a typical fence, to which the BB’s are attached, right off the table. Most fence attachment systems resist side forces better than lifting forces. In this scenario, the BB’s become the fulcrum forcing the wood against the top of the spinning teeth.

If this happens, there will be enough crazy going on that you may touch something that you shouldn’t as you try to hang on.

BB’s can help hold well-behaved stock against the fence, preventing stock rotating and touching rising teeth, but don’t skip the splitter. Pinch events can happen instantly. Once you’ve seen a board jam solid on a riving knife, or even remove a Micro-Jig splitter from it’s mounting holes, you’ll be really glad something was back there, as you knee the OFF switch and wait for the saw to coast down.

-- It's all good, if it's wood...

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