Tablesaw KickbackCauses and prevention

by Kelly Mehler

O ne afternoon, I wascutting a stack of wal-nut panels, about a

foot square, on my tablesaw.I was being careful, but therepetitive work was mind-numbing. My body was on au-topilot, and my brain wastaking a snooze. Then, wham!I was slammed in the gut, dou-bled over in front of the saw.There was no warning; I neversaw it coming. It took a fewseconds for me to realize that Ihad been hit by a piece of

Later, in reconstructing whathad happened, I guessed thata short piece of stock had piv-

oted into the back of the blade.The result was kickback.

Stock that's hurled by the ta-blesaw is pretty scary. I es-caped serious injury, but Iknow others have not been solucky. Recognizing the causesof kickback and its preventionis an important survival skillfor any woodworker.

The potential for kickback isinherent with any circular saw,and on a tablesaw, kickbackcan occur when either rippingor crosscutting. Unlike a band-saw, where the cutting forcedrives the stock into the table,a tablesaw can lift the work offthe table and throw it with

tremendous force. Under nor-mal conditions, teeth on theback of the blade, which arerising out of the table, don'tencounter any resistance be-cause they are in the kerf.Kickback results when stockcomes into contact with theteeth at the back of the blade.With the outer edge of a typi-cal 10-in. blade moving atabout 100 mph, any work-piece can become a missile.

Even though tablesaw kick-back is most commonly asso-ciated with ripping, it also canoccur when you are crosscut-ting. Cutoff pieces that vibrateor are pushed into the back of

Small offcuts vibrate into back of blade. Short stock rotates into kickback zone if not held tightly against fence.

of this common shop hazard

wood thrown off the tablesaw.

the blade can be launched to-ward the operator.

A good splitterPreventing the workpiecefrom contacting the back ofthe blade is the only foolproofsolution to kickback. This isthe job of the splitter. A bladeguard alone does not work.

Most stock tablesaw splittersare part of a 3-in-1 unit (see thephoto below left) that includesa blade guard, anti-kickbackpawls and a splitter. When in-stalled and aligned, this kind ofsplitter works well for rippingstock. But it must be removedfrom the saw when cuttinggrooves, tenon shoulders and

when the stock is not cut com-pletely through. The splittertilts with the trunnion, but itdoesn't rise and fall as bladeheight is adjusted, so the low-er the blade is set, the greaterthe gap from the back of theblade to the splitter. Conse-quently, with typical -in.-thick stock, there is a gap of

about 2 in. between the backof the blade and the splitter.Kickback can occur before thework reaches the splitter.

Another splitter, like the onein the top right photo below,has anti-kickback pawls and isused with a separate bladeguard. It mounts to the saw'strunnion and shares the same

This splitter is more likely to be usedbecause it dismounts and remounts easily.

The best splitter closely hugs the back ofthe blade and can be left in place for allcutting operations.

Anti-kickback wheels drive the stockagainst the fence.

shortcomings as the 3-in-1unit. The real advantage of thisdesign is that it dismounts andremounts quickly, eliminatingone of the chief complaintswith the 3-in-1 design.

The best design, one thatcomes closest to totally elimi-nating kickback, is the splitterthat rises and falls with theblade (see the center right pho-to on the facing page). As faras I know, this splitter is avail-able only on some Europeantablesaws. Because it attachesto the arbor assembly, it canbe set close to the blade teethand below the topof the blade. Thisis handy becausethe splitter doesnot have to be re-moved when stockisn't cut all the waythrough.

A throat-plate-mounted splitter isanother option. It'sa thin, hardwoodfin glued into ashopmade, wood-en throat plate justbehind the blade.Because this split-ter does not rise ortilt, you may haveto make several ofthem, so you have one suitedto the stock thickness you'reworking with. (For more onthis, see FWW #115, pp. 70-75.)

Other precautionsBesides a good splitter, othercommercial and shop-built fix-tures can help prevent kick-back. Your strongest ally maybe care and common sense.The tablesaw is an easy tool totake for granted, especiallywhen you're tired or in a hurry.

Equipment you can buy ormake—A fence that angles to-ward the blade encourageskickback, so make sure thefence is parallel to the blade orangled away from it slightly.For crosscutting, a crosscutbox or a fence attached to themiter gauge keeps cutoffsaway from the blade (see thebottom photo at right).

A well-designed push stickis a must for keeping yourhand out of danger. A goodpush stick holds down thework on the saw's table and al-lows you to steer the workagainst the fence (see the pho-to at right). The type that I pre-fer is shaped like a shoe and ismuch better than a stick with abird's mouth in the end.

There are several types offence-mounted, anti-kickbackwheels (see the bottom rightphoto on the facing page), butthey all operate on the sameprinciple. The wheels only al-

low rotation in thefeed direction, andthey lock when thestock is pushed to-ward the operator.The wheels are an-gled so that theyforce stock againstthe rip fence.

A featherboardclamped to a tableis a low-tech buteffective way ofpreventing kick-back (see the pho-to at right). Thefeatherboard has aseries of closelyspaced kerfs cutinto one end. The

spring-like fingers hold thework tightly against the fence,and they act like a pawl to pre-vent the stock from beingpushed backward.

Shop practices help, too. Asharp blade cuts with less resis-tance, reducing the chances ofkickback, so it's a good idea tocheck your blade regularly.Don't stand directly in linewith the blade. By standing offto the side, you'll be out ofthe way if the blade catches apiece of stock and throws it.And it pays to know when toquit. When you're tired orwhen someone breaks yourconcentration, it's time to turnoff the machine. Kickbackhappens instantly and seldomwhen you're expecting it

A typical

10-in. blade

moving

at about

100 mph

can turn

any work-

piece into

a missile.

Large push stick keeps stock against fence and holds it on thetable. Note that the author is not standing in line with the blade.

A featherboard holds the stock against the fence, reducing

Kelly Mehler is a furniture-maker in Berea, Ky.

Miter-gauge fence prevents kickback by pushing offcuts away

the chance of kickback. Mount featherboard in front of the blade.

from the blade and providing more support to the stock.