I can’t get my miter saw to cut perfectly square
Hi everyone:
I have a Makita LS1013 10″ sliding compound miter saw. It’s a fairly simple and primitive matter to adjust the fence so the cuts are absolutely square: four bolts to loosen; adjust the fence square to the cut line; then re-tighten.
Except that it’s not working. I have squared the fence to the slot in the table. I have squared the fence to the cut line in a piece of wood clamped into place. But then whenever I try to cut four consecutive 90 degree cuts on a single piece of plywood — in other words, use a piece of scrap plywood to test the angle — it just doesn’t come out square. I have wasted a lot of time adjusting hither, thither, and yon, to no avail.
Is there some other adjustment I should be fiddling with besides the fence? I have also used a guage to make sure the blade itself is 90 degrees to the surface of the wood and have made sure I am holding the wood flush to the fence when making the cut. This shouldn’t be so difficult, but it is.
Replies
Make the adjustments to the cut board not the fence or slot in the table. Also mitersaws, especially sliders, have a lot of slop--it matters that you pull down the cutting blade in the same way each time. There is a lot of holding your mouth right that is necessary, as well. These are tools designed for house building from cutting framing lumber to trim carpentry, but not really so much about precision cuts for furniture.
That's what a radial arm saw is for, but an acceptable RAS, if you buy one new, STARTS at about $1,500. Older Dewalts and Delta Turrets can be less, especially if you can deal with 3 phase power, and are handy mechanically.
First thing to know is if your square is actually square, a lot are not. Every shop should have a good engineers square for checking set ups. Next, the edge of your work piece needs to be straight to reference to the fence. Hold the square tight to the blade and fence, it should fit perfectly. As you pull the saw head forward, it should run against the square with no change. If your blade is good and the work doesn't move while cutting, that should be it.
I'm in disagreement with Steve. I've had a number of miter saws and the accuracy of the cuts are as good as it gets.
Miter saw deviation
I've got the same saw, and one of the things I noticed is that the fence - which is a one-piece unit - is not perfectly straight. When I place a straightedge on it, it is obvious that the two ends are out further than the middle.
I was able to compensate for this deviation by tightening the bolts closest to the blade first, and then reefing on the outboard ends of the fence in order to bend them into a semblance of a straight line. Doing this while simultaneously trying to make the fence perpendicular to the blade makes for a long, frustrating session. Once I got it in place I considered welding it there..
But, if I had to do it over again, I'd consider sticking down some sandpaper sheets to my tablesaw table and lapping the fence straight.
Life is hard enough. Fighting your tools makes it even more difficult.
Zolton
A couple of other (unlikely) possibilities: (1) Blades that have been abused can wobble. (2) Some carpenters pull--rather than push--a sliding compound miter saw blade through stock.
Is it possible you're getting some blade deflection? What blade is in the saw?
Thank you to all who took the time and trouble to try to help with this puzzle. I think I found the issue: the play in the fence, when loosened, isn't quite enough to get it perfectly square to the blade cut. Now don't ask me how or why that should be the case -- I may have to take this up with Makita. But paying careful attention to squaring the fence when loosened to the blade cut I found I had to move the fence to its maximum flex point to get a near perfect square cut. I can probably live with the 1/64" to 1/128" I may be off on longer 90-degree cuts though I still think this machine should be capable of delivering perfectly square cuts.
Again, thanks to you all for your help. Happy 4th.
As somebody else mentioned make sure the fence is straight, I figured out that the fence on my delta 12 saw was warped. Also check that the table is flat as well. Another thing that can cause problems is a blade that is to thin. Try a reqular blade not a thin kerf blade.
Thanks and good luck
Adirhu
My experience has been that unless you clamp the workpiece (both pieces) down and to the fence, it can move when you bring the rotating blade down into it. That is, the blade wants to rotate the workpiece back and tilt forward as it spins into the wood, Then there is also the downward thrust of the blade wants to push the board down in the middle and up on the ends. Just enough to throw the angle off a few degrees. Especially if you're used to slamming the blade through a bunch of 2X4s like I was.
Bottom fence set screw?
Mr. Gressel,
I know this is an old post but I was wondering if it could be the small set screw on the bottom fence. See the attached picture.
There is a knob on the back to lock it down when sliding ~1/2" away from blade then on the opposite side closer to the fence there is a small set screw. This was my issue - it was loose and wasn't giving me consistent nor 90 degree cuts.
If you got it, maybe this can help someone else.
Thanks but I think I got it solved
Thanks for taking the trouble so long after the original post. You must have a different model than mine because I don't have that set screw.
What finally allowed me to fix it was for me to calm down and take a scientific approach, writing down each setting of the fence as I tried each possible variation. It really didn't take me that long once I did it the slower, more methodical way. Lesson learned, at least this time.
miter saw not cutting square
Try another saw blade. I had to go through two blades before I got a square cut. The first blade said miter saw on it and cut witlh a bow in the middle. I suspect just two many teeth and not enough clearance. I next tried a Radial Saw blade with a 5 degree negative taper and got a better cut, but, not square. I finally went to a 24 tooth combination blade and the cut is good. So, try another blade first.
Scm out of alignment
I realize this is an old post but I too had this problem on my Makita LS1016. After much trial and error I ruled out all possibilities but one - a defect in the saw fence. I could not set the alignment dead square. There are four bolts holding the fence in place - two on the left and two on the right. They go thru elongated holes on the fence so that the fence can be adjusted. However these 4 elongated holes did not all line up in a straight line. As a result the fence could not be exactly positioned to be square to the blade.
I removed the fence and then ground the inside edges of the holes so that I could adjust the fence so that it would line up square. I probably should have called Makita but this did fix the problem.
Adjusting for square cuts on LS1016L
I agree with Peacefulkancer on the set screw solution. If you have an LS1016 model you should have small set screws on the backside of the bottom fence (both left and right toward the blade). Peacefulkancer includes a good picture of the set screw in his post. If those set screws are not adjusted correctly the blade side of the bottom fence can have play causing a deflection of the board you are cutting as the blade is nearing the end of the cut. It is very slight movement of the fence near the blade (again, on both sides of the rear of the fence) and it can cause the board to move back slightly near the blade. This causes you to cut out of square slightly less than 90 degrees. This can also cause the blade to bind and kick on longer boards.
I think the set screws not being properly set, causing kick back and out of square cuts, can cause other things to get out of alignment or even bent due to the force of the kick back. Even if I clamp both sides of a long board I have still had kick back on wide, thicker boards due to the slight play on the inner portion of the lower fence (controlled by the set screw noted above).
I know that this post is old but I had a problem of the exact same thing in March of this year 2020. My radial arm nor my Bosch miter saw would cut the ends square of some kitchen cabinet drawers that I'm making. But the problem was they would be out of square from only one edge. These parts or 21 in Long by 9 and 1/4 wide and 3/4 thick. I put the board on my jointer table and used a dial indicator and the two long sides were parallel within .005 of an inch so I was really baffled as to why one side would be square and the other wouldn't. And it would be out of square by almost an eighth of an inch. After trying all kinds of adjustments on both saws, I finally decided to put a straight edge on one of the long edges and sure enough it was bowed. The other side was not bowed. So what was happening was the short edge of the straight edge that I was laying on the long edge of the board was falling into that small dip. And when stretching out my 12 inch square across the short side of the board just magnified the problem. So then I use my hand jointer and flattened the bowed side of the board, checked again with the square and bingo, perfect! Now I got to figure out why the jointer was cutting one side bowed but the other side was flat. I hope this may help others down the road.
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