Mitersaw Kickback...

[Thomas Sexton]

I just had my first ever kick back and it scared the daylights out me. It's even worse because I don't know why it happened so I'm wondering if anyone has had this experience...

I was putting a 45 on a piece of Ash, very hard wood. The wood is 1 inch by 1.5 inch and about 30 inches long. I have a Makita 10 inch sliding miter saw so I set the saw, put the piece in holding it by hand and started the saw in from the front and BAM. The wood went flying and my thumb was almost broken and a plastic piece (guard) that attaches behind the safety cover was on the floor.

I cleaned and inspected everything and checked the fence and saw for alignment and put the piece back in, this time I used a hold down. I started cutting and BAM the metal hold down had sheared and I said a prayer that my hand wasn't holding anything.

I've been using the saw for a couple of years but now I'm afraid to try it since I don't know what I'm doing wrong.

Any suggestions would be greatly appreciated.

Tom S

[Steve Jenkins]

The first thought is that you pulled the saw toward you lowered it and pushed it into the wood. A piece with similar dimensions may be lifted by the rotation of the blade. You should drop the saw straight down when cutting narrow pieces.

[Eric Schmid]

When I see kickback on a miter saw it is usually caused by either the keeper or cutoff rotating or lifting. On a 30" long piece I would imagine the cutoff is moving. If you are cutting small bits off the ends, a zero clearance throat plate will help these from turning into projectiles. When they get caught in between the blade and fence, they can cause kickback. Always wait until the blade is fully stopped before lifting the saw head!!!

At this point I would be checking the blade and fence again. There may be more damage. Make sure the blade is spinning true and that it is sharp. Check the fence with a straight edge and for damage.

It may be that your hold down was not secure on the second cut. If you are sure that it was tight, then you have cause for concern. Something, in that case, isn't right. It could be as simple as not lifting the saw head until the blade stops, however.

[David Kumm]

I've had that happen when cutting wide Hickory. Make sure any end tables are not higher than the saw station but support the board, and I take shallow cuts with hard wood. Score it half way down and finish the cut by chopping down and not sliding forward or back. My slider is my last choice for wide hard boards. I think part of the reason is the kerf isn't much wider than the plate on SCMS blades. Dave

[sebastian phillips]

Well, some people call them "chop" saws, and use them as if they are chopping wood, but they aren't chop saws.
There are two separate points to consider to avoid this:
1-Make sure your stock is flat and has a straight edge (aka jointed and planed) . Before cutting, make sure the board is flat to the deck, and pressed against the fence (both for accuracy and to prevent the blade pulling and/or grabbing).
2-Let the blade come up to speed before plunging. If it's an especially wide or less than perfect piece, make your cut in two or more passes. Do not ram the saw through the material the minute you pull the trigger.

"Advanced techniques":
1-If you are cutting small return pieces for crown/stool, etc, and having trouble with the keeper flying away:
Do not bring the saw up after completing the cut-keep it in the down position until the blade stops spinning. A little pause saves tons of time and aggravation.
2-you can cut less perfect stock on the miter saw, but you've got to understand the physics. If your board won't sit flat, you may have to lift it up as the blade passes through, giving the offcut room to drop (usually you're doing this when rough cutting).
However, some boards are better cut with a circular saw, especially when breaking stock down.
I can cut a 20' (even green and twisted) 2x12 in half without lifting it off the floor:
Roll the board on edge
Put your left foot under the half way point
Let gravity take your circular saw through the board as you slightly raise your left foot.
The offcut drops 1/2" to the floor, the keeper stays on your foot.
Production framers cut all day, accurately, like this with heavy boards. Easier than lifting them onto horses and dealing with binding.

Anyway, sorry for the novel. Think about the forces acting on your material before you cut. Take your time. Use sharp blades.
Seb

[Myk Rian]

The saw lifted the wood with the back of the blade.

[Ray Newman]

Agree with Steve Jenkins. In my experience, especially with small pieces, make the "chop", turn off the saw, then let it coast to a stop before lifting the blade.

[Bill Space]

The saw lifted the wood with the back of the blade.

At first I thought, wow, obviously this has to be the case, since the front of the blade is moving down, and the rear of the blade would be moving upwards.

I don't use my miter saw much, and I do use my radial Saws much more. Frankly, it never occurred to me to pull my miter saw beyond the wood, and then to lower it before making the cut while pushing backwards. This seems like a recipe to have the wood jump upwards, if it is not held down securely, or perhaps I should say VERY securely…

I know there is a trade-off, and that on the radial arm saw, or a miter saw, when you make the cut in a forward direction the blade tends to want to self feed, since that is a climb cut mode.

So I would say to the OP, if you make your cut in the forward direction, you will probably not have to worry about the kickback that you experienced. But you do have to be careful about the tendency for the blade to pull itself into the wood.

Bill

[Wayne Lomman]

First, cutting small sections like this you always just pull the saw straight down.

Second, NEGATIVE RAKED BLADES stop the climb cut problems. It's a basic engineering solution to a common safety issue. Should be mandatory on all drop and radial arm saws. Cheers

[Lee Schierer]

Before using the saw again, check every single tooth to insure they are all there. One or more of them could be bent, broken or missing.

Most likely your cutoff, which was triangular shaped, moved and the teeth caught it and it acted like a wedge between the blade and the back support. A zero clearance insert will help prevent this problem.

[Thomas Sexton]

Thank you for the input. As several of you pointed out the small end-cut was wedged in the back opening. I've always thought the only way to cut was from the front... without really thinking it through. I can see now that w/ a small piece like this on the miter saw, I should come straight down on it... or use my table saw :-)

Thanks again. Tom

[Sam Layton]

sebastian's number 1 and 2 are spot on... If the wood is warped and/or not against the fence, and/or binds a kick back can occur. I have had a couple of violent kick backs where the wood was warped a bit, and not properly against the fence.

If the wood is bowed in the middle, away from the center of the fence, but touching the fence on the ends, and you bring your blade back and start your cut by pushing into the wood, the cut will finally allow the wood to collapse against the center of the fence, causing the wood to pinch the blade, and kick back.

Sam