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Kickback Incident on Table Saw

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15K views 55 replies 24 participants last post by  Ocelot  
#1 · (Edited by Moderator)
This incident happened back in September. I took photos at the time but forgot to post them. I just was reminded of it when reviewing old shop photos today.

I have a Ridgid table saw with no riving knife.

I know better, but once in awhile I want to rip a short piece. This one was about 6in long. The photos should tell the story.

I can't recall now if I was wearing the full face shield or safety glasses. I was using the guard, which kept the projectile low so that it struck me in the belly rather than in the face. No injury, but a warning all the same.

To reconstruct what happened, I show the pieces as they were before I ripped them apart.

Image

Showing with guard up only to illlustrate. The distance between the blade and the spliitter was more than the length of the piece being ripped. Not a good thing!
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The guard was down like this.
I was pushing with a push stick as shown, between the guard and the fence.
The feather board was set so that it applied pressure only before the blade.

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The cut completed without incident and the keeper piece (against the fence) was pushed clear of the blade.

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At this point, I had the not too bright idea of using the push stick to flick the cutoff piece away from the blade, while the saw was still running. If I had turned off the saw (as I usually have done) and waited for it to stop, there would have been no problem.

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Unfortunately, my touch was off - and instead of pushing the piece away from the blade, I pushed the near end of it away from the blade, causing the forwared end of the cutoff to rotate into the back of the blade - resulting in the kickback. For the photo, I've raised the guard (which was down in the actual incident) to show what happened. The blade picked up the piece and (especially since it was trapped under the guard), began to fling it toward me.

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The cutoff continued to rotate as it passed over the blade (under the guard).

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Continuing…

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This is the resulting cut on the bottom of the cutoff.

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6 inches is too short to rip on my saw!!!

Pieces to be ripped need to be long enough that the cut off piece will reach the splitter, which will restrain it from rotating into the back of the blade.

-Paul
 

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#2 ·
Anytime I am cutting something that small, I use my crosscut sled. I have never had a problem when usint it.
I did have a very bad kickback about a year ago with my other saw. The piece hit me in the chest and I thought I broke some ribs. I went to one knee and stayed there for awhile.
That is when I made my first crosscut sled. I have one for larger work up to about 24" and one for slall pieces about 12" or less. Never had a problem with either.
 
#7 ·
I would use the bandsaw, but I've got a Wixey digital readout on my table saw, and not on the bandsaw. I really like being able to rip to a very precise width. I do rip rough lumber on the bandsaw though.

I'd like to upgrade to a saw with a riving knife.
 
#11 ·
push sticks do not control either the work piece or the off cut. Push sticks can not accurately apply force to the block in a specific direction. try pushing a smaller piece of wood as was cut here with a push stick and you will see that you have to correct the path constantly. the feather board BEFORE the leading edge of the blade is ok but there is nothing to guide the block after separation is made , pushing the block on the outside corner drove the back corner into the space between the splitter and the blade. Glad that you weren't hurt. sad that this lesson has to be learned over and over by others. Shutting the saw off before clearing the blade is not a safe practice either. On your saw there is no brake on shutting down but on those saws where there is when the brake injection happens there is just enough flex in the works or the blade for it to get a purchase on the material and kick it. I use a sled for picture frames and production cuts at times. I do not have a Gripper but they do have them where I work they are a very good piece of equipment! other types of feeding stock can maintain very good control also. Never have I liked the use of push "sticks".
 
#12 · (Edited by Moderator)
Ocelot - I've been doing this a while as I'm sure a lot of others.

1. I know I'll catch hell for saying this, but I'm going to say it.

Get rid of that thing you called a guard.

The only thing it guards is the company against a lawsuit. IMO its worse than not having one at all. If you had been able to see your work, maybe you could have stopped the cut and avoided the whole thing. My old Xactasaw has a similar piece of junk splitter and I have never used it once from day 1. You need something right behind the blade. Unless you can retrofit a riving knife, use can either make your own or get something like the MicroJig splitter system.

2. You should be using zero clearance inserts. Make or buy several of them. f you go with the Microjig or a homemade splitter you need one anyway, and one for angled cuts, one for a dado blade, etc.

3. Try using a different push stick than what you show. I think push sticks are actually dangerous unless you're really minding the store. They work ok but not for short pieces because they tend to put pressure at one point. Plus you need to use two of them so you don't have one hand free to do a quick shut down. A simple 2×4 with a small heel on the end works much better, but if you're paranoid about getting your fingers within 6" of a blade make it a 2×6. There's plenty of demos out there on making these.

4. Last but not least, check the slot/blade/fence for parallel just to rule out that possiblity.

IMO If you could have seen your work, had a decent splitter and used a different push stick, this might not have happened. That being said, ripping short or thin stock are two of the highest risk operations.

Who said the most important safety device in the shop is between our ears?
 
#14 · (Edited by Moderator)
Thanks for all the posts.

@Ghidrah,

I think it must just be the angle of the photo. The featherboard was before the blade. I should have photographed it straight down from above. In the last 2 photos, I think the featherboard had been moved. Maybe that's what you're looking at. The first few photos show it exactly where it was, since I had clamped a little improvised hold-down on it and it's still clamped I can see in the 1st photo. In any case, the pieces were well past the featherboard when the cut completed.

@REO,

I can't imagine using a 2×6 for a push stick. It would be too heavy for me! I use thin sticks with a step on the end. I can apply down pressure, side presure and push at the same time. In this case, the push stick I don't think was an issue during the cut. I completely agree that the push stick does not control the off-cut.

@rwe2156,

Thanks for reminding me of the micro-jig splitters on a ZCI. That would also have prevented the iincident. On the other hand, I've had this saw for 15 years and always use the guard for through cuts (not, obviously for grooving cuts). Without the gaurd, there is no splitter at all - which is, in my opinion, worse. I've never had any problem seeing the cut. Also, the guard in this case kept the flying piece down low - preventing it from flying up into my face. I may have had a full-face shiled on (I sometimes forget to use it), but even so, I'm sure I'm better off getting hit in the belly (where I have some considerble padding), than in the face.

-Paul
 
#22 ·
Well, I bought the face shield a year or so ago - can't recall why. I keep forgetting to use it. It's hanging sometimes on the arm of the RAS.

Main reason I got it was safety glasses don't work as well over my vision glasses as I would like.

They are only $10 bucks at Amazon right now, so you can imagine that they're not exactly bullet-proof. It's just a thin sheet of polycarbonate (like Lexan). That stuff is pretty tough though.

http://smile.amazon.com/MSA-Safety-Works-641817021569-Shield/dp/B0042TO6F0/ref=sr_1_5?ie=UTF8&qid=1426634378&sr=8-5&keywords=face+shield
 
#23 ·
Ocelot, I have thrown all my push sticks away!! I use only push shoes that are long enough to keep the workpiece from climbing up the back edge of the blade. If I'm ripping a longer board, I use my push shoe and a hand held featherboard with a rabbet along the edge to both hold the board down and against the fence. I'll try to find my pics for you.

For the record, I took both my blade guard and riving knife off my saw shortly after I bought it and have not missed either!
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#24 ·
You should not have your feather board beside the blade! Ahead of and or behind, never beside the feather board forced the mat into the blade which shot it back, simple physics.

- Ghidrah
Click to expand...
That was the first thing I noticed in his pics!

Next I'd reccomend Grippr's they hold downward pressure on both sides of the blade.
 
#26 ·
Thanks for your comments, guys.

@gfadvm,

Well, I'll take your word that it works for you, and I can understand why some people would remove the guard, but I still can't figure why you would take off the riving knife. There are a number of people on LJ who have gone to considerable lengths to retrofit riving knives onto old saws which didn't have them. I'm sure a riving knife would have prevented this from happening. Was it prone to get out of allignment? What was the issue that led to it's removal?

When you said "push shoe", I was imagining something else - something like a mini-sled.

@bonesbr549,

The feather board, at the time of the incident, was not pushing beside the blade, but before it. I've written this twice already on this thread. (I promise I'm grinning while I type). It had been moved before the last couple of photos were taken. The feather board, in any case, was no longer contacting the piece when the kickback occured.

The photos, being a reconstruction, don't exactly match what happened. In particular, the cutoff never was as far forward as it is shown. The end nearest me was just past the leading edge of the blade, where it would naturally stop after separating from the keeper piece on the other side. The photo of the bottom of the cutoff gives a clear indication of where it was in relation to the blade.

-Paul
 
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