Kickback question

[lcm1947]

I just got to ask this question because I am just not clear on it. Just exactly when does this kickback happen? At the beginning, during or at the end of the cut. Also I am thinking that just the material that's between the blade and the fence is what is thrown back but that doesn't seem right unless kickback only occurs at the end of the cut. Could somebody clear this up for me please. I am hoping that the whole piece isn't thrown back or I am really not understanding.

[bmyers]

Great question that should be asked and definatly ISN'T stupid to ask (before it happens).

Most times kickback is after you cut the piece free. The blade grabs the piece of you just cut wood and twists it, pinching it between the itself and the fence. After that it's just in the way and spinning your way already, time to duck.

Usually it's because you and not holding onto the piece between the fence and the blade. Most times the piece is wider than it is long.

Rememeber a few simple rules:

1) Don't use the SMT AND the rip fence at the same time.

2) Always hold the piece of wood thats between the fence and the blade with something, let the other piece fall away. Maybe not your hand if it can't safely fit in there, but with something to push it through.

3) Use the stock blade guard. (PERIOD)

Do a forum search for kickback for a more indepth explanation.

Bill

[ChrisD]

Lee, more info is available here: http://www.taunton.com/finewoodworking/pages/w00066.asp

And in this article by our very own Ray Girling ("RayInTheUK"): https://www.sawdustzone.org/articles...mare-explained

[LCHIEN]

kickback happens when the cutoff betwenn the fence and the blade gets picked up by the rear of the blade (which is rising from the table). As it gets picked up it tries to rotate because the teeth catch it. Pieces that are roughly square and 3"-6" on a side seem to be most prone. the back teeth of the saw making it rotate it now jams hard because the diagonal is longer that the sides. The teeth finally get under it, gouge the bottom as they go by, and hurl the piece at you about 100 miles per hour.

I might add the best way to prevent lickback is not to use the saw, haha. The next best way is to use a push shoe and make sure the cutoff piece is held down firmly (don't let the blade do the initial lift at the back) all the way through the cut and finally push it out back past the saw blade.

[Stytooner]

Kickbacks can happen with full stock during the cut as wll. If you are cutting a sheet of plywood and it starts to bind or float away from the fence, it can start to rise and come toward you twisting and spinning.
They can also occur by the kerf pinching the back teethof the blade durig a cut with such force that it leaves no other option but to come up and back toward you. Likewise if the kerf was to splay out and put pressure on the fence, it might get in a bind on the blade and kickback.
These and the others explained in this thread can be very dangerous
The good news is that the types of kickback that I described are virtually non existant when a riving knife is installed.
Not using both fences at once helps prevent another type of kickback.
There should never be a board left between the blade and the fence after a cut. This is the board that should be pushed clear with a push stick or shoe. The offcut can be left to its own devices while you take care of the one that could cause the problem. If your guard is in place, it shouldn't go anywhere anyway.

[JimD]

I read both articles and agree with them and Lee and Loring's comments. I'll add a couple. First, both articles say that you are not to use the SMT (or miter guage) with the rip fence. This is true unless you put a stop block on the rip fence that is out of the way when the cut is made - the rip fence is not touching or near the wood when the cut occurs. At least recent shows by Nahm use this technique. I have a little stop block in a drawer of my BT3100 just for this purpose. It can be a handy technique for making multiples as long as you use the stop block and not just the rip fence. I have an auxiliary fence on my rip fence with a T groove in it that the stop block is attached through. I slide the stop up near the blade to set the distance and then slide it back toward the front of the saw for use.

Second, I will add that, particularly when using the SMT, you can have a small offcut vibrate over into the blade and become a projectile. I have had this happen but not on the BT3100. Vibration is low with the BT3100 and I use the riving knife. I also use a push stick or piece of scrap to push suspicious off cuts away from the blade.

Jim

[lcm1947]

Thanks everybody for your replies. I have a much better understanding now thanks to you all. So if I am getting it right basically; keep the piece against the fence at all times with special attention at the end of the cut, control the piece all the way through the cut using a push stick if needed and last always use a splitter whenever possible. So if that's correct then I think I've got it thanks to all of you. Again I appreciate it Gentleman.

[MilDoc]

So do I. Best explanations I've seen. Thanks to all.