Dewalt 780 miter saw kicks back

Hobby_Man22

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This saw occassionally gets the blade pinched in the wood that im afraid to hold the board with my hand. I just use the board clamp thats connected to the fence. I sent the blade off to be sharpened and that pretty much fixed the problem, but it did it and few times again cutting some treated 2x6s. I started taking small relief cuts to release any tension in the wood. I suspect those last couple times, the board may have had a slight twist or warp to it. Any tips on preventing this? The slide was locked too.
 
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RonnieC

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I’ve never had a kickback on the miter saw but it stands to reason that if the board is bowed and cutting it leads to the cut portion closing in on the near side of the blade that it will jam up.
I would either run it through the jointer first or cut it with a circular saw with the waste end hanging over the edge of the sawhorse. The jointer may end up removing too much thickness over the length of the board so probably circular saw.
 

rlitman

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...The slide was locked too.
Reactive wood can pinch a blade, but it's uncommon in a cross cut on a 2x. Usually that happens on rips, which is why it's more of a tablesaw problem. If the slide was locked, I suspect the board wasn't sitting square and tight to the fence. It's an issue when it has twist or cups along the fence. Pay attention to if the board rocks on the table, and if there's a gap behind it when pressed against the fence. In either of these cases, once the single board becomes two, those gaps under and behind it can close, allowing the wood to shift, and that can pinch the cut.

Things are always made worse by a loose hand hold. A firm force into the fence and a slow cut usually works fine, and use your ears to pay attention to how the motor is straining. As you near the end of the cut, if the remaining connecting wood fibers start to bend, allowing the blade to start to pinch, you should hear it slowing unexpectedly as the wood rubs on the blade plate, and immediately stop cutting. Either flip the board to finish the cut, or use that bending wood to your advantage (with the saw stopped and up again) and press the board truly flat against the fence so you can restart your cut.

Also, are you using a tablesaw blade in a miter saw? I ask, because tablesaw blades typically have a lot of tooth rake (hook angle) that helps pull the work down to the table. That same rake wants to lift the wood in a miter saw. That's way they make special low rake blades for miter saws.

positive_and_negative_rake_1024x1024.jpg

Finally, if you are using the slide, always pull it out, then drop the saw into the wood and push back towards the fence. Pulling it out while down is a climb cut, and that's very dangerous when woodworking.
 
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mm08822

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I haven't experienced kickback on a mitersaw, but pinched the blade a few times and that started the ruin of the belt.

Check for bowing, place bow up if possible or towards you.

Sometimes I have shimmed one side to prevent pinching.
 

LXCam

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Is this happening right after you release the trigger?
 
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jar944

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How long of a treated 2x6? Sometimes a circular saw and a speed square is the right tool.

There is no inherent tension within a board on a cross cut. You are not supporting the board correctly if it's grabbing the blade.
 
OP
H

Hobby_Man22

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How long of a treated 2x6? Sometimes a circular saw and a speed square is the right tool.

There is no inherent tension within a board on a cross cut. You are not supporting the board correctly if it's grabbing the blade.
10ft, but i have it on a dewalt miter saw stand with supports for the board
 

tyyost

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Ideally, I’d ask you to describe what you mean by kickback. Given the geometry of a miter saw with the correct blade it is unlikely to behave like a traditional kickback to push the saw out of the cut. If the work is supported on a stand and all is relatively flat the only thing that can cause the saw to jump back is pinching the blade.

If your lumber is twisty you may want to consider using a speed square as a guide with a circular saw of your choice, letting the offcuts fall away.
 

neophyte

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Miter saws kickback.
I’ve had it happen on multiple brands.
It can happen if a long piece of wood is not properly supported and shifts during cutting.
It can happen when cutting down rough lumber to size if you don’t have access to a larger radial arm saw.
It can happen if small pieces of cut off wood get jammed between the blade and a zero clearance insert or fence.
Miter saws have significantly less mass in the head than older radial arm saws, and are therefore more likely to get “kickback” from any issues, particularly with the sliding compound miter style saws.
 

gahrajmahal

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Some years ago now I taught an adult education class on carpentry. Most of these students were brand new to any type of wood working and we had an excellent text book I inherited from the former teachers. Working in the day students workshop we had access to all of their “well loved” or abused power tools. Most all were corded. We had one 12” Dewalt sliding miter saw with an extended factory style mount. All the circular saws had bent baseplates and dull gummed up blades. We did have the largest cabinet style Saw Stop table saw.

Since the day students were learning how to build houses the material available to me and my students was pine 2 x materials and rough plywood and particle board. My project I developed was a set of folding saw horses with mitered, glued and screwed legs and a 2 x 6 top.

sawhorse.png

I was not interested in teaching anyone how to use hand tools such as hand saw, hammers, chisels etc. that is a safe easy task that students could learn on their own. I encouraged everyone to bring in their own tools to use, especially if they needed help in understanding them.

It seems that all the lumber was the cheapest available and we spent lots of time learning how to sight down a 2x 4, study the end grains comparing it to the photos in the text for least likely to bow in the future, then cutting lots of unequal length legs with two 15 degree ends parallel to each other.

I had built several ingenious wooden fixtures, allowing the students to relatively safely cut their four 15 degree miter pockets in their 2 x 6 with a circular saw. The 2x 4 legs slotted into these pockets. Two being glued and screwed and the opposite side being hinged from below typically using repurposed door hinges. It had a folding plywood shelf locking it into open position.

We had seven week, three hour sessions to build these sawhorses. Some students finished them in three weeks and some never completed them.

Now back to the OP’s question, cutting twisted structural lumber and kickbacks from his sliding miter saw. Seeing all these folks of various skill levels struggling to use this unwieldy giant 12” Dewalt saw without a soft start feature that kicks somewhat hard when pulling the trigger, then requiring brute strength to pull it out, over the top of the lumber while simultaneously having to push a long twisted board flat in two directions against the base and against the backstop. They still haven’t done the cutting part which is push the saw down then forward SLOWLY through their board.

033 - Copy.JPG

Most couldn’t do it initially, with practice or sometimes ever. I myself own a 12” Dewalt Chop Saw. No sliding feature at all for two reasons. I don’t like using a sliding miter saw and they are much bigger to store. So, after watching several classes struggle with this saw I found I could lock out the sliding feature and turn it into a Chop Saw. Eliminating this strength challenge and motion brain challenge was very beneficial to my students. They could position their twisty boards then only have to pull the saw down slowly to cut their sawhorse legs and tops.

They discovered to cut four 2 x 4 legs of equal length it worked best to cut them all ganged together and not one at a time.

Meanwhile, some students avoided the miter saw and attempted to build the project using Only a circular saw. The logic being they didn’t own a miter or chop saw and why learn to use it. I also had devised a clamped and ganged method of cutting four equal length legs working off the many large tables in the shop. They were angling the circular saw base to 15 degrees, clamping and using a cutting guide.

So, bindings saws? Yes, I had many a situation. Mostly when cutting boards a student would suspend the board across two sawhorses, then try cutting in between the supports. It got so I intentionally showed them this phenomenon an and they were encouraged to practice cutting scrap boards while hanging off the support. Slice, slice, slice. Difficult pushing the spring loaded blade guard out of the way, keeping the shoe flat and watching videos of YouTubers doing it wrong. Many were manufacturers demonstrating their products!

Eventually I made a “shooting board”, well, that’s what I called it. It was a sacrificial board with a low stop screwed to the back. It screwed to the top of my example folding saw horse which was conveniently made the same height as the shop benches, that way a long 2 x 4 or 2 x 6 could rest on the shooting board and the bench being completely supported. A 12” quick square is held in place and the circular saw is visually lined up with your cut line. You can push really hard to cut and also easily clamp the loose end to take the twist out. If a student was particularly weak, it was easy to double hand the circular saw holding the saw guard open, then taking a slow cut on their drawn line.

I had students old and just out of high school, men and women. With physical limits and folks who worked in the trade and were teaching me new tricks.

DSCN0947 - Copy.JPG

Using a shooting board is my preferred way to cut structural lumber to size. I used it on 90 percent of the cuts when building my son’s rear deck stairs. I had my chop saw set up, but preferred a quick square and circular saw. My go to is a Metabo 7-1/2” battery saw. So great because of long battery life, powerful motor and soft start feature allowing no jerking on startup and less fatigue in wrists and arms.

I’ll try to dig up some photos to go along with this explanation. Here is an internet photo showing the crosscut shooting board fixture.

IMG_1666.jpeg
 
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