Would a splitter have prevented my kickback?

[Rob Blaustein]

As a beginner concerned with safe technique, I read with interest Cliff Newton's post and responses (http://www.sawmillcreek.org/showthread.php?t=6789). Glad you're OK Cliff. I didn't want to "hijack" that thread so I'm starting a new post, though it is closely related--apologies if it belonged there. In the spirit of sharing mishaps with the hope that I and others can learn, I present my beginner's kickback tale:

Got a new Grizzly 1023SL and after getting a new subpanel installed in my basement (yikes, that set me back a bit) with some 220V outlets I was quite eager to give it a whirl. I had already aligned the table, fence, etc. after reading some articles on properly aligning a saw, as well as the alignment chapter in Jim Tolpin's Table Saw Magic, so I figured I was all set. So I pick up a scrap piece of plywood that was around 4" x 6" x 3/4" (I can already hear the groaning) and decided to rip a thin strip off. I should say that both of those long edges were true. For some reason, I thought I'd just remove about 1/4" so I set the fence at around 3 3/4" to the right of the blade, put a featherboard to the left of the piece to push it into the fence (I did keep it behind the blade), picked up a long piece of scrap to use as a pushstick, raised the blade maybe a 1/4" higher than the piece, turned on the saw, pushed the piece through and watched the blade effortlessly start slicing. Then it happened. Just as the cut was finished, I watched the thin strip (i.e. the waste piece) fall into the cabinet through the slit in the insert (the stock one that came with the saw) and then in one instant there was a grinding noise and the rest of the piece just disappeared in a blur and as best as I can tell from the sound behind me, hit the wall and bounced around a bit. Thankfully I didn't get hit because one of the only smart things I did was not stand behind the blade. I'm not entirely sure what happened, and I welcome your thoughts, but my sense is that since I didn't hold the piece down with the pushstick, and only pushed forward with it, the leading part of the piece (the part closer to the back) somehow lifted up after the cut was done, caught the rear of the blade, and got hurled right back at, as Dennis P would say, Mach 3. So if you'll permit me some self-assessment, here is my slightly more educated view of what (I think) I did right and what I did wrong, and please let me know what you think.

Right:
1. Wore safety glasses.
2. Stood to the left of the blade.
3. Used a featherboard and made sure it was just behind the blade.
4. Used a saw that was properly aligned.

Wrong:
1. Tried cutting a piece of wood that is pretty small without some special sort of jig. I have read that many do not advocate cutting such a narrow and short piece at all on a TS. I recently bought a Grr-Ripper to help with something like this (it is not my intent to start another Grr-Ripper debate here).
2. Didn't use a splitter (or blade guard). Got the microjig splitter now, but my main question is--would a splitter have prevented this?
3. Didn't keep downward pressure as I cut. I now realize that is very important. A Grr-ripper, an auxilliary fence with a featherboard pushing down, or a proper pushstick would probably all help.
4. Used a bad pushstick--basically leading to 3 above. In fact it's possible that pushing down on the piece with that pushstick caused that leading part to lift up.
5. Didn't use a zero clearance insert, which let that waste part fall down--not sure if that contributed, but I now have a zero clearance insert.

-Rob

[Scott Parks]

Rob, sorry to hear that you're already learning the hard way. Glad to hear you were not hurt! I think your assesments are pretty accurate.

I would contribute the waste "kick" mostly due to the lack of a zero clearance insert. However, I'm not sure I understand if you paced your featherboard correctly. If your featherboard is behind the blade, or behind the cut, it is forcing the waste peice against the blade, and the back of the blade, thus pinching it. This is what a splitter will prevent. (The pinching).

As for a push stick, what you're using sounds inadequate. By pushing with a stick, it allows the back of your peice to lift off the table. The Grr-Ripper would prevent this, or a push stick that also holds down your peice. Or even a featherboard on the fence that holds your peice against the table.

So your question on the splitter... I don't think that is why it kicked. And yes, it is safer... Hurry up and install that MicroJig! (Oh, and the dust collector:) ) And count those ten fingers one more time...:)

[Rob Blaustein]

Thanks for the input Scott--I realize now I was not being clear. I should have written that I had the featherboard just in front of the blade. And yes, I'll install that splitter before doing any more ripping!
-Rob

[Mike Kelly]

Rob, the 6" length of the board is too short to use with just a push stick. No splitter would have helped I suspect since the distance from the front of the blade (start of cut) and the splitter is usually more than 6". The Gripper or something similar would be the only safe way in my book. Maybe a hold down pushstick? You also may look at your fence alignment to the blade. Some folks use a little larger spacing at the rear of the blade (maybe 1/64") compared to the front to insure there will be no pinching under normal conditions.

Glad you weren't damaged. Hopefully we can learn more from other's quicker than we can make any more mistakes! Even with the Gripper I have blown it! http://www.sawmillcreek.org/showthread.php?t=5785

[Lee Schierer]

I am happy to hear that you are unhurt. I think your problem was the result of the thin piece falling through the throat plate. It probably kicked the blade to the right and pinched the piece being cut. I never cut anything on my saw without a zero clearance insert. My "Factory" inserts are hanging on the wall and never get used.

I would also suggest you use a push stick that holds the piece down as well as pushing. You can buy one or make your own, but use one.

[Jim W. White]

I've used this "ergonomic" model over the past 5 years since finding it at WoodworkerSupply.

I've gone through a few of them now. Keep one that I use for sacraficially thin peices and one new one at al times. I trust this one so much I've started handing them out for Christmas gifts to my friends who woodwork.

..Jim in Idaho

http://woodworker.com/cgi-bin/FULLPRES.exe?PARTNUM=922-377

[John Shuk]

First I want to say I am glad you were not hurt. I goes to show how important it is to be out of the line of fire. Just to add to what has been said. I witnessed a nasty kick back and while there was no splitter as well as other circumstances which added to the kickback the girl who had it happen stated that she saw a piece of the cutoff fall down into the insert as you describe. She may have been unduly distracted by that and moved the wood away from the fence into the blade causing the kickback. A splitter and proper positioning would have kept it from happening but what seems important is that I don't think we need to worry about the piece on the non-fence side of the blade. Even if it drops through the insert I don't think it poses a danger and we need to more or less ignore that in leiu of watching the piece between the fence and blade. If I am off base here let me know. I think accidents are usually a confluence of factors coming together.

[Ted Shrader]

Rob -

Glad you were not hurt. In your list of "right" things, you give yourself credit for where you were standing. Good!

Your analysis of the events is probably right on the mark. Thanks you for posting and reminding all of us how quickly things can go wrong.

Regards,
Ted

[Lou Morrissette]

Rob,

Welcome to the Creek. Glad you came out of it ok. Scary stuff!:eek: As others have stated, I think the combination of too small a workpiece, improper pushstick and a little distraction may all have led to your episode. Every day's a school day.:D

Lou

[Rob Blaustein]

Thanks for all of your suggestions and encouragement!
-Rob

[Chris DeHut]

I believe I read your comments correctly, but as always, the written word can be confusing.

You mention that the featherboard was behind the blade? From and operator point of view, behind the blade would be the far side of it. You do not want to position a feather board anywhere in line with the actual cut when ripping.

Rather, position the feather board in front of the blade (nearest to the operator). If the feather board is in line with the blade, it is in essence pushing the kerf closed against the blade which is going to cause kick back.

Second, and perhaps even more important, is the way you described the cut. It almost seems as though when the off cut fell into the saw, you stopped feeding the keeper piece. Worse yet, is that if you left the keeper piece between the blade and the fence without being under control. This again is a sure fire way to turn the work into a bullet.

I am a GRR-Ripper fan (no surprise to anyone here). When cutting on the table saw (or any machine for that matter), you have to maintain control of the workpiece at all times. The more control you have, the less chance of problems. The GRR-Ripper system is the only device I have used that gives me a tremendous amount of control over the workpiece. With it, I can easily feed work over and past the saw blade while at the same time maintain full control of the work. This control is in 3 directions...

1) Forward to cause the cut
2) Down against the tables surface (prevents lifting of th part)
3) Towards the fence to prevent the keeper piece from walking away from it towards the blade.

Take some time to learn more about the GRR-Ripper, frankly, I believe it is the best safety device to come out for woodworkers since safety glasses.

Chris DeHut

[Jason Sanko]

I am happy to hear that you are unhurt. I think your problem was the result of the thin piece falling through the throat plate. It probably kicked the blade to the right and pinched the piece being cut. I never cut anything on my saw without a zero clearance insert. My "Factory" inserts are hanging on the wall and never get used.

I would also suggest you use a push stick that holds the piece down as well as pushing. You can buy one or make your own, but use one.
I would not say my "factory" inserts never get used. They are very helpfull in routing new "zero clearance" inserts. BUT that is the only thing they do get used for.

[Rob Blaustein]

Chris--thanks for the suggestions. As I said in a f/u post, I incorrectly said that I had the featherboard behind the blade--I was confused about terminology--it was in front.

Jason--yes, I had to use the stock insert as a template too, since my zero clearance insert was a little too large to fit into the slot. I also used it to start the cut in the new insert. I'm sure many of you know and use this trick. Even with the blade all the way down, I couldn't fit the new insert into the slot since the flat bottom of the insert hits the blade (I gather there are some that have a groove already made to facilitate this). So I put the stock insert in but lowered it all the way down with the set screws which left a small amount of room that could accommodate the new insert on top of the old one. I clamped it, started the saw, raised the blade into the new insert to get the cut started, stopped the saw, took out the stock insert, put in the new one with its partial kerf, clamped the fence over it (leaving room for the blade obviously) and then made the kerf.

[George Grubaugh]

One more thing to consider. I rate the safety cross cut sled I built after Dave Knipfer's posting, as one of the most essential devices for the table saw.

In the interest of safety can I post this link?

http://woodworkstuff.net/CCSledA.html

Good luck with the new saw!

[Cliff Newton]

I'm glad you're okay Rob. My kickback actually occurred several months ago, but someone recently drudged up my old post. Although mine happened a while back, I'll never forget it. Pretty scary, huh?

I've taken a few protective measures since then in the form of always using my splitter and an improved push shoe device. And I always stand to the left of the blade and I make dang sure no one is standing behind me.

[Tom LaRussa]

2. Didn't use a splitter (or blade guard). Got the microjig splitter now, but my main question is--would a splitter have prevented this?
I think that a properly positioned splitter would probably have prevented this, and a riving knife, (which is like a splitter, but which for reasons technical is located closer to the rear edge of the blade than a splitter can be), almost certainly would have.

I think what happened is this:

As the piece of wood which you intended to keep began to pass beyond the back edge of the blade it got skewed slightly sideways.

When this happens the edge of the board closest to the blade can come into contact with the teeth at the back edge of the blade.

This causes the board to lift up take a ride over the top of the blade and thence across the room or into the gut, chest, or cranium of anyone standing behind the saw.

The splitter is intended to prevent this contact between the wood and the back edge of the blade.

The reason I say that a splitter probably would have prevented this is because there is often a gap between the splitter and the blade. This gap gets wider when the blade is lower and narrower when the blade is raised up higher.

A riving knife, on the other hand, is connected to the same thingie that raises and lowers the blade, so it can be adjusted at a constant, (close), distance to the blade.

HTH,

Tom

p.s. Somebody please correct me if I've messed this up.

[Alan Turner]

Rob,
I am a fan of a specialized pusher which is free, made from scrap wood of just about any sort. Make the height about 6" or so, and the length about 8", up to 15" or so. Cut a notch from the bottom, about 3/4" deep, leaving about 1" at the back. Easier to draw than to describe. With this pusher, you automatically keep pressure on the whole board, not just the very end. And, you can run the pusher right through the blade with the stock on a narrow rip cut, which notches the pusher, but so what. I rip stock down to 1/8" or less, in safety.

[Mark Stutz]

Rob, I use a single cutter from my 8" dado set to make the kerf in a new ZCI. Clears the insert just fine and you don't have to worry about perfect alignment of the new to the old.

[Mark Singer]

The Push stick Alan described is key.

Board Buddies...with only the back one in for this application.Very important!

Having the fence set a 64th out of parallel with the blade...wider in the back so it doesn't bind.

A splitter keeps the wood from binding on the blade...with experiene you can see this as your cutting

[dale rex]

http://www.leevalley.com/wood/page.asp?page=30067&category=1,42207,49759&ccurrency=2&SID=this is what I always use. I dislike push sticks because they always seem to tip the stock as you are pushing.

[Marshall Harrison]

Mark,

You said to set the fence a 64th out of parallel with the blade...wider in the back. Wouldn't this cause problems with making parrallel cuts on longer boards as the board is going through the blade at an angle and the two sides wouldn't be parrallel? The angle is slight but it's still there.

[Mark Singer]

No!
It is how my saw and many others are set up.It still cuts perfect and does tend to bind at the rear half of the blade which is the part where the rotation is lifting the piece toward you. This will help prevent binding and kickback and will not disturb the straightness of the cut since you are pushing toward the fence. 1/64 is maxium...it should be set with a feeler gauge.
Marshall scroll down on the attached post until you find Bob Smalser and my comments....

http://www.sawmillcreek.org/showthread.php?t=14888&highlight=kickback


Mark,

You said to set the fence a 64th out of parallel with the blade...wider in the back. Wouldn't this cause problems with making parrallel cuts on longer boards as the board is going through the blade at an angle and the two sides wouldn't be parrallel? The angle is slight but it's still there.

[Marshall Harrison]

Thanks Mark.

I looked at the post you referred to and I use the same typo of push stick as Bob.

I can see where offsetting the rear of the fence could cause some binding on the rear of the blade. I'm a programmer and perhaps too analytical but that's what makes me a great programmer. I know that a lot of woodworkers offset the rear of the fence but it still seems to me that the sides would not be parrallel unless but both sides were cut using the same fence. If you use a factory edge against the fence the the ripped board would be wider by 1/64th at one end.

The only exception I can see is if the board is not kept pressed flat against the fence beyond the blade. If that is the case then the rear of the wood actually rides 1/64th inch away from the fence meaning it is still straight and parrallel with the front of the fence. Is that what is happening?

Note: I'm not doubting you I just want/need to understand how thisworks.

[Mark Singer]

Marshall,

The front teeth and rear teeth cut independently...It is still parallel... it is as if there were 2 sets of cutters offset by a 64th. So the kerf is larger but all is still parallel. It is even reccomended in Mark Duginske's Book Mastering Woodworking Machines...He is an inventer and anexpert in machine set-up. You could go a bit less than a 64th also. I have been cutting like this for years and years and everything is nice and parallel:rolleyes:

[Paul B. Cresti]

Rob,
First off the most important thing is that you are ok.
Yes always use a splitter. Yes always use a blade guard and yes you need to push down on the wood and against the fence through the entire cut. In addition a zero clearance insert should be the first thing you make. Let the cutoff do what it wants to but at the same time do not be afriad to turn off the machine if it is sitting in a funny spot.

This also brings to mind the notion of how we work. I would not have tried to rip a piece that small on a table saw. I would have used the bandsaw without a doubt. Another way to do it is to rip longer pieces and then cross cut to length. What I have switched to is rough ripping on the bandsaw and then running the pieces through the planer to the desired width. Now this works only up to a certain width & length. Accidents can happen to any of us. The most seasoned ww'r or of course the novice. If you do not feel comfortable about an operation stop and rethink of another way before you proceed. I could get into the whole American vs European ww'g machnery deal again but I think most people know where I stand on that...

[Marshall Harrison]

Thanks Mark!

You finally did it. You convinced me when you said that you have essentially two sets of cutters offset by 1/64 inch cutting independently creating a wider kerf. That makes sense to me. i knew that a lot of people did it I just couldn't understand how it was working.

Sorry about being so stubborn. Thanks again for taking the time to explain.