My first kick back in years. No one is hurt since I remember table saw rule #1: stand to the side.
I was cutting a rabbet with a table saw blade and the waste material kicked back at the end of the cut.
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A good post to see for those who ask questions about children, pets, and visitors in the workshop. That would have gone through somebody's eye socket and out the back of their head.
Excellent point.My entry door is locked when I'm working for that reason and so nobody sneaks up on me.
No kids, no pets, and no onlookers when the machines are running.
The risk, however slight one considers it to be, is simply not worth it. God only knows how many ways a multi-horsepower piece of machinery can maim or even kill.
Go idea to lock the doors.
I don't know if I would lock the door- if something bad happens, nobody could get in to help. Oddly enough, I had a piece of scrap do the same thing to my door but the inside is metal so it just went in and made a hole like yours. About the same size, too. I knew it was going to happen and stood to the side as well. There was no good way to keep it from happening so I just let it go. My hands were more than 6" from the blade so I really didn't have anyhting to worry about.
"I cut this piece four times and it's still too short."
Good point, but there are keys in the house and the garage door can be opened with the car opener or touch pad. I have two small girls that have what seems to be 50 little friends always playing around our yard. The likelihood of one of them sneaking in when I'm working is far greater than me getting so hurt I can't open the door.
Just out of curiosity... Were you cutting the rabbet in such a way that the offcut was trapped between the blade and fence?
My question exactly. It should be cut in an order which allows the offcut to "fall harmlessly" to the side, no?forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
F.G. , yes the off cut should NOT be on the fence (RAS or TS) but in '88 we didn't have the pretender in plaid or Knots for education etc. just our drive to get it done. It has not happened since and will not happen again as I use zero clearance inserts with splitters on the contractors saw or Unisaw, smarter technique and only use the RAS for cut off or miters.
I had my first table saw, a wooden Gilleum(sp) from post war -no metal- in '68 and bought the RAS in ?'72. How old were you? Ha. All the very best, Pat
"How old were you?" Old enough to have fun, but not old enough to know better. ROFL!!forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
Fence was to the right of the blade and the offcut was to the left of the blade.
If the cut was made with the blade to the outside, the cut usually won't be quite as consistant. Kind of the same way a routed rabbet is made with the cut edge on the router fence. The best way to make this particular cut on a tablesaw is by using a backer block behind the stock and follow it through, past the blade.
"I cut this piece four times and it's still too short."
Since I've used a router or dado for almost all my rabbets, I'm flying on theory here, but my understanding about cutting rabbets with a tablesaw is that you make the 2 cuts such that the 2nd one has the offcut falling away from the blade, and the stock itself is between the fence and the blade.
Here's an illustration from page 149 of Mr. Mehler's book, illustrating the order of cuts. I'd think a featherboard would help keep the stock stable if necessary.
View Image
Suggestion from Mr. Mehler -- if it's necessary to have that 2nd cut on the other side of the blade (next to the fence), fasten an auxiliary fence that's raised up off the table so that the cutoff piece has somewhere to escape to without pinching against the blade.
forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
Edited 9/26/2006 2:06 am by forestgirl
That illustration is how I did it. The only exception is that I used a feather board on the first cut to keep the stock flat to the fence. That feather board was not used during the second (kickback) cut.Note: a featherboard is NOT a good idea during the second cut since it will definitely cause a kickback! (Pushes off-cut into blade)
"That illustration is how I did it." Shows the wisdom of layering safety precautions!
"a featherboard is NOT a good idea during the second cut since it will definitely cause a kickback! (Pushes off-cut into blade)" If it is raised up on a spacer such that it presses above the area to be cut, shouldn't be a problem. But it may not even be necessary.
forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
Edited 9/26/2006 11:23 am by forestgirl
OK - so we've got
1. the second cut for a 7 foot long 1/2" wide x 3/4" deep rabbet/rebate,
2. stock against the fence,
3. off cut to the non-fence side of the blade and
4. probably no splitter or riving knife to keep the saw kerf open right behind the blade
5. the cutoff accelerated as it was being hurled away from the blade.To initiate the kickback the side of the cutoff has to
a. contact either the rear INSIDE or rear OUTSIDE teeth of the blade
OR
b. twist so the top blade side of the cutoff can contact the saw teeth behind the cut.For the kickback to actually occur, there must be nothing stopping the cutoff from moving foreward - towards the front of the saw - ie no wood in front of the cut.(i.e. and e.g. - english majors? Which is correct for this use?)A riving knife, unlike a "splitter", wraps around almost the top rear quarter of the saw blade (where the kickback demons lay in wait, as someone in another thread described it) and can be set very close (1/8th inch or less) to the teeth. So it keeps the kerf open and the offcut AWAY from the rear teeth. Normally, to allow a blade guard to attach to it, the top of the riving knife is above the top teeth of the saw - so it can't be used when making blind cuts such as the one in question. BUT they're easily "modified", being made of aluminum. The problem is that they're typically not easy to get on and off quickly. So let's skip a riving knife as a solution to this kickback problem.Before getting to the "What could've been done to prevent this kickback?" Let's look at alternatives to doing the rabbet/rebate the way it was done - on a seven foot long board - ie "Is there a safer way to do this?" A seven foot long rabbet/rebate? Was this necessary or could the stock have been cut into two or more shorter, more managable pieces? (tall bookshelf sides make it necessary?)Could a stacked dado set have been used - no cutoff to worry about, featherboard(s) can be used to keep the stock down on the table and against the fence and a push stick with a wide "heel"?Is the stock wide enough to support a router and a rabbeting/rebating bit with a guide bearing for routing out the material?Is the stock narrow enough to use a router with an edge guide and a dado bit?Could the cut be made on a router table, either with a rabbeting/rebating bit with guiide bearing or with a straight bit and a fence?Looks like there were several safer alternatives to the method used but skip that.What could've been done to avoid the hurled javelin (sp?)?Well what if
A. the cut off was between the fence and the blade?
B. a modified riving knife was used to keep the kerf open
C. a push "stick" with a sacrificial "heel" were used near the end of the cut to control BOTH the stock and the cut off 'til they're both passed the rear of the blade?Remember - the cutoff accelerated as the kickback began. It was the last few inches of the cutoff that probably contacted those spinning rear teeth. At that point the cutoff didn't have much momentum or speed. The "heel" of the push stick could probably stop the cutoff from moving long enough to push it passed the rear teeth.Another possible solution - a few brads. After the first cut, put a few brads on the cutoff side to keep it temporarily connected to the stock during the second cut?More ideas?charlie b
(i.e. and e.g. - english majors? Which is correct for this use?)
I was a chemistry major until I flunked calculus, but "i.e" means "that is" (latin "id est") and "e.g." means "for example." ( I forget the latin)
e.g.=exempli gratia
Ughh...that was long. I'll answer a couple easy questions since I'm hungry and dinner is done:A riving knife MAY have helped, but what I observed was not a rear tooth type kickback, but the offcut rubbing on the side of the teeth and rapidly gaining speed until it shot off the table.Perhaps a 2-3 foot piece would not have enough length to gain such speed. I needed the pieces very long because they are the stiles of the two side panels I am making for a cabinet. This rabbet is to receive the 1/4" back panel.Dado set would be fine, but I didn't want to change my set-up for a couple of rabbets.That's a lot of good theory, but...the only thing I'd do different is put a piece of scrap plywood against the garage door to stop that big dent from happening!EDIT: The brad idea is a good idea. Fast and simple (like myself). I'll do that next time. Thanks.
Edited 9/26/2006 7:25 pm ET by Mumda
OK, maybe I'm just bleary-eyed from working on some taxes here, but how can you use a riving knife when you're completing the 2nd cut of a rabbet? You're completing a non-through cut! (actually on the 1st and 2nd cut).forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
Good question and this answer is speculation since I have a US saw without a riving knife but; I believe a riving knife is just shorter than the crown height of the spinning blade, even when lowered as low as necessary for a rabbet cut such as mine. Maybe this riving knife would have kept my offcut from engaging the sides of the saw teeth.Maybe not since (I assume) a riving knife is thinner than the kerf of the saw blade?
A riving knife sits below the top of the blade so it can stay in place while making non through cuts.
"A riving knife sits below the top of the blade so it can stay in place while making non through cuts." I forgot how magical they are (to us heathens in the US). Thanks for reminding me!forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
The feather board can be placed ahead (closer to the front of the saw table) of the blade, too. That way, there is no pressure against the side of the blade at all.
"I cut this piece four times and it's still too short."
Nope. Waste piece was left side of the blade. It was the last of four pieces and I had no problem with the other three.
M. Wow that's unusual. Do you think the legnth was a contributing factor and caused it to flop into the blade? Pat
Edited 9/25/2006 10:22 pm ET by PADDYDAHAT
Yes I do think it was the length. It was 7 feet long, and I could see it gain momentum as it rubbed the side of the blade.
M. I wasn't so lucky as you( oh, I stand to the side also so it wasn't me) I had the garage door open while ripping a big chunk of red oak on a 10" RAS, the spear went through the grill and radiator of HER (SWMBO) beautiful Mercury station wagon only 3 mo. old. Boy that was a tough wallk from the shop into the house. " Honey I had a little accident...." , We have all done it, we were both very lucky. All the best, Pat
Edited 9/25/2006 7:38 pm ET by PADDYDAHAT
Oh boy...
Sorry for the damage to the car, but very happy YOU weren't hit :)My goal is for my work to outlast me. Expect my joinery to get simpler as time goes by.
Wow. Good thing you didn't get hit with the spear. I had the exact same thing happen this past winter (first time in about 10 years). Cutting the bevel off some crown moulding, and WHAM!!!! My piece went right through the steel siding on my shop, and 3/4 of the 10 foot long cut off was sticking on the outside of the shop.
The first time I had kickback, I wasn't so lucky. I cracked 2 ribs in 95' (had to ask the wife for the date) when I wasn't out of the way. When I stumbled in the house, she thought I had been shot, cause I couldn't breathe too good, and couldn't talk, either; blood on the shirt, you get the drift............
Good post!
Jeff
Ouch man! I can see how bigger pieces would get you even standing to the side.This was strange; it was almost slow motion happening because I could see it starting to rub the blade, then pick up speed, then WHAMMM!!!!
Very lucky ! Now for our benefit, Do you use any of the safety features supplied with the saw. Splitter, Guard of antikickback pawls ?
I've had problems with the kickback pawls on small pieces like yours, they tend to push small pieces any which way or cock the piece into the blade. Don't use them at all any more. But the splitter is still in place.
Work Safe, Count to 10 when your done for the day !!
Bruce S.
It wasn't a through cut, so none of that stuff could be used for this operation.
The kickback pawls would never come in contact with the piece that flew- he was cutting a rabbet.
"I cut this piece four times and it's still too short."
Yes, you are correct about the pawls. I was remembering a near kick-back while doing a through rip. Sorry.Work Safe, Count to 10 when your done for the day !!
Bruce S.
Your waste piece was trapped between the saw blade and the fence with nothing to hold it from firing back. When making connecting cuts, like a rabbet, have the waste piece fall to the left of the blade, not between the blade and the fence.
When I was a teacher, I bought some safety tapes. One was on the table saw. The operator in the film was doing exactly what you were doing. His pieces were short and you could barely see them go shooting off camera. In this case, the safety film did it's job in reverse, showing what not to do. I ran into a lot of safety films like that. Obviously, the editors didn't know anything about the subject.
Beat it to fit / Paint it to match
How many times does he have to reply saying his offcut was NOT trapped between the blade and fence!?!
Thank you BigFrank!
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