I have a question regarding the safety of a cut I need to make on my contractors table saw ( I need to do about 5 of these panels). My initial instinct would be to categories the cut as ‘using the fence as a stop to do cross cutting’. What I am trying to do is depicted in the attached sketch. When you edge joint many planks like this to form a solid board and perform a ‘rip’ on the length of its end grain, is it still considered cross cutting? At the end of the day I want to know if the cut can be made safely.
Replies
Looked at the sketch. Are the pieces glued together prior to cutting? If so, no problem cutting them as illustrated. If they are not glued, and you are trying to gang cut a bunch of pieces like this, disaster lurks.
Mike Hennessy
Pittsburgh, PA
Hi Mike, thanks for advise. They are already glued together.
Ricardo
What about using a Felder or maybe a Knapp?
They are more expensive, but much less than good health.
Qara
The cut is across the grain so it would technically be considered a crosscut, and you would use a blade made for crosscutting.
The set up is for ripping and the safety concerns for ripping would apply no matter which way the grain runs, or to put it another way, the operation wouldn't be any safer or more dangerous because of the grain orientation.
John W.
If the boards are glued or clamped tightly, you can make the cut and it would be considered a crosscut. How you cut is not the issue. The issue is how the blade orients to the grain of the wood. If it is cutting across the grain, it is by definition, crosscutting.
Now, as to safety. It is very risky to use the fence for a cut when the front to back dimension of the panel is less than, or about the same, as the left to right dimension. There is a danger of the panel skewing an that is a frequent cause of kickback. The right edge of the panel must be kept in solid and continuous contact with the fence all the way through the cut.
Personally, I would recommend using your miter gauge or a panel cutting fixture.
What are the dimensions of the panel? Assuming it is a reasonably size to handle, this cut (technically a cross cut) should not be a problem. Judging by your picture, it looks wide enough that you can use both hands to hold the panel down and tight to the fence without being anywhere near the blade. Be especially careful to keep the far end of the panel tight to the fence as you complete the cut so as to prevent binding and kickback. Do some run throughs without the saw on to find the best place to stand and best ways to hold the piece during the cut.
"There is a danger of the panel skewing and that is a frequent cause of kickback. The right edge of the panel must be kept in solid and continuous contact with the fence all the way through the cut." [Howard in #5] IMHO, this statement cannot be overemphasized! Please close your eyes and envision that panel lifting up and floating over the top of the blade, spinning directly into your body and dragging your hand across the blade! [As the board spins away at Mach5, your hand follows but not as quickly, and is soon without the protection of the board underneath it.]
I've had this happen with a 3/8"-thick piece of plywood, and I've talked to a cabinet-maker who nearly lost his hand when this action happened.
I've never tried to cut anything like your panel (squarish, thick, heavy no doubt), but since you have 5 to do, seems like it would warrant making a sled? or is it too big for that?
How thick is the stock?? Since my near-disaster, I take extra precaution when cutting nearly-square panels. I clamp a board to the fence, making a "channel" for that edge of the stock to ride in (stock rides on the table, with the edge of the board above). It just barely touches the stock, preventing it from lifting up, thereby keeping it from being able to drift up and over the blade. If I were cutting the panel you illustrated, and sled was not an option, I would make an auxillary fence, tall enough to give room at the top to clamp my channel-forming board.
forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
Do unto others as you tell them they should do unto you....
Edited 2/1/2006 1:22 pm by forestgirl
I think there is a lot we don't know here, that depending upon the answer will make the cut relatively safer or riskier, like:
How big is the panel? Can you put one hand at each end throughout the cut safely?
What is it's relative shape? Close to square? Or wider than long?
How thick/heavy is it? That is, how easy to control?
How much is being cut off in the process? A shaving to get the panel parallel after taking most off with a curcular saw is a lot different than cutting a panel made of 8/4 in half etc.
Let's assume it's a manageable size panel - squarish and roughly 24" on a side and no more than 1" thick - and that I'm making only a small trim cut. Keeping it tight to the fence ane down on the table should not be too difficult - your hands will be a long way from the blade. You could even stand to the right of the fence and essentially pull the panel edge tight to the fence to stay even further from harms way.
"Can you put one hand at each end throughout the cut safely?" Sorry, I wouldn't depend on that approach. Not to say I don't sometimes put one hand at each end, but if I need to turn loose of the far end, I want to be able to do that without the risk of the panel spinning around and nailing me.
Looking at his sketch, I'm not assuming <1" thick. You're right, we need more information.forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-) Do unto others as you tell them they should do unto you....
I'd determine whether I could keep my hand there throughout the cut before making the actual cut by setting the fence wide and doing a run through with the saw off. Choreograph your feed technique first, so to speak.
One way or another, we all need to control any board we cut throughout the cutting procedure. And one had better figure out how they're gonna do that before starting the saw. Ad libbing with the saw running is an invitation to trouble.
Hi all, thanks for the advise, apologies for not including all the info. The dimensions are 30mm (1.5 ") thick and it is a square measuring 700mm X 700mm. It is made of pine and is reasonably heavy. No more than 1" is being cut off.
Hi, Rick,
I would heavily endorse those views from Howard and Foestgirl - be careful, and by far the best advice I can give you is to make sure the riving knife, or splitter if your saw is as old as mine, is in place and adjusted correctly. This could save your face - literally.
Good luck,
Ozzy
The fact that the panels are fairly thick and heavy works in your favor -- the spinning-kickback phenomenon is more likely to occur with a lighter piece of stock. And the fact that you're only cutting off one inch is definitely in your favor. But you must be sure that block stays against the fence and on the table all the way through the cut. I'll be interested to see what folks think is the safest table-saw approach.
Just fantasizing (because I've never cut a panel like that): If I had a knee-operated shut-off for my saw, I'd probably just run it by the blade using both hands on the stock. Without a bumping-type shut-off, I think I'd make a sled with a clamp. But then, I'm chicken <g>.forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-) Do unto others as you tell them they should do unto you....
Hi Rick,
Definitely use a crosscut sled. They are soooooo safe, piece can be clamped, almost NO CHANCEof kickback,and are extremely versitale, accurate and simple to use. If you have Fine Woodworking #128, Lon Schleining shows you the correct way to make a very accurate sled.
Also, you will find many uses for it in the future. Mine also does double duty as protection for my TS's top when not in use.
Bob @ Kidderville Acres
I also agree with what others have said, but with a panel as large as yours, I don't believe kickback will be too likely.
700mm is 27-1/2 inches. Kickback is always a concern and something to be aware of. But in my experience, it happens alot more with smaller pieces.
One thing to keep in mind is that it is the leading edge of the cut that is so important to keep tightly registered against the fence. You want to concentrate on keeping even pressure against the fence at both ends of course, but a major cause of kickback is the part pivoting counter-clockwise as it is pushed along, (assuming the fence is to the right of the work). This causes binding and well, you better duck!
I see this often when people use push-sticks. They start the cut with both hands holding the stock. As the cut progresses they pick up the pushstick with one hand and engage it at the back edge of the piece a couple of inches away from the fence. Their leading hand begins to get uncomfortably close to the blade, so they let go and they continue pushing with the stick.
If the pushstick is too close to the fence as it pushes the stock through the cut, the piece can pivot counter-clockwise. You can illustrate this by taking a piece of printer paper and putting your finger behind at the lower right corner, pushing it forward. The paper will pivot counter-clockwise. Same thing can happen to your square panel stock.
I think this is a major cause of kickback. Even with all the safety devices in place (which they should be), you still need to be vigilant about applying force correctly against the fence all the way through the cut. Or you're in for a world of pain!
Now put your finger behind the center of the piece of paper, just to the left a bit. Push forward and see what happens. Now it goes straight and ever so slightly clockwise. A piece of wood can't really pivot when pushed this way. The leading edge wants to gently pivot clockwise but is prevented from doing so by the fence. The trailing edge cannot really move because it is being held by the push stick.
But as large as your piece is I think it could be held safely through the cut. If, however, you are uncertain, you could always lop it off with a hand saw or a circular saw and dress the edge with a block plane (end grain) or a bench plane (side grain).
David C.
A featherboard before the blade won't hurt, either, as you've relatively little leverage to pull the board to the fence in your illustration.
If a crosscut sled is not available, and cannot be made, use a featherboard at the leading edge of the blade and just after it to hold the panel against the table.1 - measure the board twice, 2 - cut it once, 3 - measure the space where it is supposed to go 4 - get a new board and go back to step 1
A second feather board past the blade is risky, it can pinch the off cut against the blade.
John W.
Sorry, I did not clarify. I use the featherboard attached to the rip fence, so the pressure is down against the table, not flat on the table pushing against the rip fence. This keeps the board from being lifted by the blade and flying back at you.
1 - measure the board twice, 2 - cut it once, 3 - measure the space where it is supposed to go 4 - get a new board and go back to step 1
Edited 2/9/2006 1:46 pm ET by Ricks503
Ricky,
I would listen to what Howie said. My only kickback experience came doing something similar to what your contemplating. When the board kicked back, I reflexively pushed back with both hands. Thankfully, I pushed the board onto the blade and bent it over, which stopped the saw.
The relative dimensions are the problem. Ripping usually involves boards significantly longer than wide, making it easy to keep against the fence with absolutely no rotation of the stock. You might be o.k. with feather boards etc, but, if it were me, I would invest the time in making a cross-cut sled (having had one heart pounding experience too many).
Matt
Ricardo
Let's assume you really want to trim both ends so you are going to make 10 cuts. Even if you never cross cut again you will not regret making a sled just to do this job. Best thing you'll do all week-end.
Now about this cricket final .............
Don
Edited 2/4/2006 12:25 am ET by dondownunder
Use a sled, in forty something years of professional wood working I have had three kickbacks. All three were due to using a fence for a crosscutting operation. You would think that one kickback would have taught me a lesson. It did, but only for about a dozen years or so.
mike
I agree, using a sled is the safest way to do crosscuts, especially on a big slab or odd proportions.
However, as an alternative if you don't want to make a sled ( and I have used this numerous times ) you could just use a circular saw with a sharp crosscut blade help firmly against a firmly clamped straight edge on the slab lying flat on a bench.
I have cut solid table tops that were way too big for my contractor saw and you wouldn't know the difference.
Soarthumb
Hi,
At the dimensions you gave, this is a straight forward and safe cut. Frankly, people are making it sound far more complicated and dangerous than it is. As well, the position of the operator in the diagram using the brett jig is dangerously off balance and would never be allowed in any professional shop, mine included. The operator must stand behind the piece so that they are balanced before, during and after the cut. Trying to stay out of the kickback zone as shown will only greatly increase the chances of kickback. The one specific safety step required in your case is that the edge running against the fence is absolutely straight. This can be accomplished by running a router or circular saw against a straight edge to establish this first edge.
When I began woodworking, I learned how to deal with sheet goods from carpenters for whom cutting up sheet goods is a daily task and I still, when the dimensions are big or awkward, use a straight edge and circular saw.
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