Table Saw Kickback

[John K Jordan]

I tend to set the blade higher rather than lower. Only the leading edge of the blade should be doing any cutting if your saw is properly aligned. The teeth at the rear are in the kerf that was cut by the front teeth. The rotation of the blade and cutting action of the teeth is putting downward pressure on the piece being cut, hence a higher blade height puts the down force more directly perpendicular to the table surface. The lower the blade above the top of the wood, the downward force is much less creating the greater the chance the piece will climb up the blade as it is pushed into the blade.

That is exactly how I was taught. Teeth just clearing the top of the wood direct any force at the cutting point forward. Teeth angling down from above the blade direct that force more towards the table. Of course, the kerf the back of the blade rides in must be constrained from pinching and causing the wood to rise, with alignment, technique, splitters, hold-downs, guards, and wood choice. If the idea of a low blade is to reduce tooth exposure to minimize damage to fingers i suspect safety efforts might be better directed elsewhere.

The extreme example of downward cutting force is the bandsaw. Bandsaws have their own safety issues but kickback isn't on the list.

[Corey Pelton]

I use the Jessem clear cut guides, though I've never had an issue with any kickback on my saw. The guides are great for keeping the work tight to the fence and the table.

[Norman Pirollo]

I've been following this thread and when I hear kickback, my ears perk up. Experienced it 2-3X many years back and made it a mission to understand it fully. Otherwise, I would not be comfortable using my 3HP Unisaw. So I always use a splitter when ripping (with pawls). This in itself can stop kickback. Ensure fence is aligned correctly to blade. On crosscuts where fence is necessary for repeatability, only have a partial fence that ends at front of blade. I also use a sled often, feel it's safer using this. Also never stand directly behind the saw blade (line of fire). So I take all the precautions.

Having said this, I went further with this and developed an anti-kickback system for table saws. I spent last fall developing it and it works. It just needs to be integrated into new models of table saws, so hoping to have manufacturers jump on board. It dynamically brakes the blade in kickback situations. The momentum of the blade is dissipated enough to eliminate the force of kickback. There is a demonstration of it in a YouTube video for those interested. I wear gloves and safety glasses only for the demo and stand completely to the side as well ( for demonstration purposes).

https://www.youtube.com/watch?v=oHlJNb86gLM

Enjoy,
Norman

[Patrick Walsh]

Oh sigh....

Skinny pieces are dangerous come on. Throw a zero clearance insert in “if that” and get some work done..

Omg this topic is exhausting.

I’m half poking at you cuz I feel I can. The other half is actually telling you how I feel.

Sure tablesaw are dangerous. So aren’t most Woodworking machines. I’m not suggesting to be reckless but I just don’t get the safety you no what’s. Imop fear is more dangerous than anything maybe even stupidity.

So many things one can partake in “risky behavior or ventures” fear must be overcome. And before anyone saiz it a healthy respect and knowledge must still be applied, stupidly can take the place of fear.

All Im saying is it never seeses to amaze me how many people are truly afraid of tools. It’s like how can you not get over something you do ever day at some point.

And sorry a tablesaw is pretty darn precise for ripping stock if well setup and you don’t use a push stick for every cut. And when it’s not and if precision is that important surfaced four sides is the only real answer.

Call me stupid and I’m sure many do but there times I’m so committed to my workpiece being the hours I have into it that taking a slight risk with my body is worth it to me. A knowledge of how wood and machines react and how to balance counteract and predict these situations takes one a long way to avoiding accidents. But if you’re always scared you’ll never get there and accidents imop that much more prone.

I apologize Brian for dropping this in response to you lol..

But not really.

The pad-style push blocks give me pause, they cause the operator to push the material over the blade. It's my understanding that kick-back is entirely more dangerous (it is always dangerous) if you're physically extended past the blade. A kickback at that position increases the likelihood of the operator traveling over the blade, which is a situation I would personally want to avoid.

I don't use a tablesaw for rip cutting, very much at all. I have a bandsaw and a planer so I'm happily making parallel edges with machinery more suited to it. I'll use the tablesaw mainly for ripping wide panels when the need arises.

Skinny pieces and short pieces are dangerous.

[Brian Holcombe]

Just be glad I’m not afraid of milling machines

I make kumiko and I know some people who use a tablesaw to bring it to thickness, I use a planer and every joint fits identically when complete.

[Patrick Walsh]

Well using a table saw to dimension for such a task is kinda ridiculous.

Not because of the danger but because of as you said the fit.

Even large material I insist in surfaced and sanded four sides as anything else is just futile regarding ease of executing reliable repeatable and clean work..

No I’m just lucky u have one and will entertain my nonsense..

[J.R. Rutter]

I just set blade height low initially and as the zero clearance insert wears, it gets raised so that it is cutting fresh at the tip of the carbide teeth. Riving knife and overarm blade guard though...

[Carlos Alvarez]

I've had a few mild to major kicks, all before I learned how to perfectly align a saw. That was almost ten years ago, and not a single incident since then. I spent close to two hours aligning every single part to within 1/256th and now there's no drama, much less friction, much less noise, no burning edges.

[Pat Barry]

I've had a few mild to major kicks, all before I learned how to perfectly align a saw. That was almost ten years ago, and not a single incident since then. I spent close to two hours aligning every single part to within 1/256th and now there's no drama, much less friction, much less noise, no burning edges.

You can do all the alignment in the world and that won't help when it comes to ripping a board that wants to grab the blade.

[Brian Holcombe]

Yes, and you can use a bandsaw for those board.

[Carlos Alvarez]

You can do all the alignment in the world and that won't help when it comes to ripping a board that wants to grab the blade.

The alignment prevents the board from wanting to grab the blade. 100% so far for me.

[Frank Pratt]

The alignment prevents the board from wanting to grab the blade. 100% so far for me.

That's actually a dangerous conception to have, but the "so far" part you've got right. Yes, perfect alignment can reduce the incidence of kick back, but not nearly as much as using a riving knife/splitter and guard, and most importantly, user technique. Even all that may not save you if you get a crazy piece of reaction wood.

[Carlos Alvarez]

That's actually a dangerous conception to have, but the "so far" part you've got right. Yes, perfect alignment can reduce the incidence of kick back, but not nearly as much as using a riving knife/splitter and guard, and most importantly, user technique. Even all that may not save you if you get a crazy piece of reaction wood.

All of these things are important together. WITH the splitter and guard, I still had some kicks before I aligned the saw. Misalignment probably starts the problem, the others are still important. I've never cut without the splitter, and almost never without the guard.

[Patrick Walsh]

Ok I’m gonna have to argue about this.

Sure any tool/machine can be used for a myriad of tasks but if a table saw is not suited towards ripping I don’t know what it’s really for.

Any you don’t have to name off a list for me as I full well know the variety of tasks a tablesaw serves.

Ripping on a bandsaw safer ok but better suited sure if you have a nice enough saw that the blade does not defect on iota. I know even a tablesaw with a regular blade I’ll often run a blade surfer to reduce defection and that’s 1/8 thick 10” blade not some rinky dinky bandsaw blade on some rinky dinky bandsaw. Now if you have a pro level or rather I should say industrial level bandsaw fine but most don’t.

As for toe in and toe out. Sure that’s one potential cause but far from a across the board solution or cure. If you think so you surely have not spent much time behind a tablesaw to experience the myriad of situations that can create kickback. The most simple is tension in a board. Often this tension let’s loose without much of any warning and when it does you had best have nerves of steel and laser focus as to not flinch and cut your hand off.

But again. If a tablesaw is not better suited to ripping lumber well then a bandsaw well then I must not know how to use a bandsaw and I actually do and I have a very nice and capable. I prefer to rip on the tablesaw and I guess part of it is I’m just not the slightest scared of pretty much any machine.

When I climbed ice, Rick and alpine mountains it was a common knowledge that fear meant you were in over you head or operating outside of the boundaries of your abilities. I’m not suggesting that be the case for anyone here and surely not you Brian but I think the theory kinda holds water in most but not all cases.

As oppinion Ted as I am on the topic this is Woodworking and everyone should do what they feel safe doing and what they enjoy doing as the whole thing is about enjoying at the end of the day.

[Derek Cohen]

I’ve always viewed kickback as having a singular cause - when the workpiece contacts the rear of the saw blade, which then causes it to climb up the blade. This is explained and demonstrated very well by Roland Johnson in a video by Fine Woodworking: https://www.finewoodworking.com/2008...a-riving-knife

Preventing kickback should be very simple - just do not allow the workpiece touch the back of the blade. A riving knife should do this. However, in practice there are other factors to consider. For example, one cannot use a riving knife when sawing blind cuts, such as grooves.

I generally keep the blade high for two reasons. The first is that this ensures that the riving knife is always high enough - a low blade has a yet lower riving knife, and the workpiece can move over it into the blade. The second reason is that the angle of the teeth is more vertical, and this does not allow the workpiece to climb over the blade and shoot forward, as it can with a low blade.

All is not safe yet. I have a Hammer K3 (slider). Kickback is highly unlikely (in my understanding/experience here) when ripping on the slider, where the workpiece is fixed and the off-cut runs parallel to the cut. Kickback is more a feature of ripping against a rip fence, where the workpiece may be forced into the blade.

When using the rip fence, I have noted how a workpiece may be lifted and ejected. I have been puzzling why this occurs, and the reason I have come up with is that the blade cuts a fine kerf, and that the ejection is a milder version of kickback - that is, the teeth at the rear of the blade can lift the workpiece. This is controlled when ripping on the slider as the workpiece is secured at the front and rear. But I use the rip fence as well (mine is a shorter, 49” slider). I added a finger board to the fence, and this has stopped any lifting ...



As a result if this thread, I revisited my thoughts on the dynamics of ripping and recognised that the rip fence can do more. There is the obvious issue of a fence that is poorly aligned with the blade and will push the workpiece across and into it. That is not my concern. Instead, what I wanted was to ensure that the side of the workpiece stayed tightly to the rip fence and did not wander off it, which is largely down to operator error (how we push, and from what angle we do so). The finger board does not control this. All it does is hold down the workpiece.

In my surfing the Net, I again came across the JessEm Clear cut Saw Guides, and now understood them better. These not only hold the work down and prevent it from moving backwards, but importantly also force the workpiece into the side of the rip fence.



Expensive, but I caught a discounted special, and ordered a set. It is on its way, so not feedback as yet. At the least, I expect cleaner cut when using the rip fence. Plus it should make blind cuts much safer.

Regards from

Derek