DeWalt 12 inch miter saw cuts are off

[ABBEY thomas]

When i set my miter saw up using a wixey gauge for accuracy, it won't stay true.
I set the vertical( perpendicular) at 90 degrees and bring the arm( blade) down not running i loose 0.3 to 0.4 of a degree. It won't stay at 90 degrees. If i move the blade to 45 degrees for a miter its the same.
On a 6 inch wide board that i am trying to make a jewelery box from, corners are junk, bad miters. They are off almost 0.025 from the top to the bottom.
I sent an email to dewalt and the response was take it to a service center.
Does anyone have a recommendation for repairs?
Thanks, abbey thomas

[Thomas McCurnin]

The repair would be adjusting the fence. I would loosen both fences and push one out of action. Then using a framing square and a pile of scrap move the fence in and out until you can cut 90 degree cut that is clean and repeatable. Then engage the second fence so it is parallel or I guess the word might be co-planar. It should cut correct at 90 degrees. Then move the carriage to test your 45 degrees.

I don't know of any other way to adjust a miter saw. That's how I do it, and quite frankly, I can get mine more accurate than a service center, but then again, my process takes about an hour.

[Pat Barry]

Please clarify if holding the 90 degree angle is to the base or the fence. Tom's discussion above relates to the fence. If its the base there are different things to consider.

[Art Mann]

Is it correct to say that the blade does not remain perpendicular to the table as the arm descends? That is what it sounds like but I am like Pat Barry in that I am not certain as to how to interpret your description. I am also uncertain as to what is off by 0.025.

[Paul F Franklin]

Also, is this a slider, a compound miter, or an ordinary miter saw? Perhaps the model number would be useful too.

[Mikail Khan]

Consider using a table saw sled for the box making while u get this sorted out.

MK

[Kyle Iwamoto]

Consider using a table saw sled for the box making while u get this sorted out.

MK

+1. Personally, I think you're asking a bit too much for a miter saw to be within .025" over a 6" span. A table saw sled would be much more accurate. Assuming of course, you have a good table saw. Just my $0.02.

[Doug Dawson]

When i set my miter saw up using a wixey gauge for accuracy, it won't stay true.
I set the vertical( perpendicular) at 90 degrees and bring the arm( blade) down not running i loose 0.3 to 0.4 of a degree. It won't stay at 90 degrees. If i move the blade to 45 degrees for a miter its the same.
On a 6 inch wide board that i am trying to make a jewelery box from, corners are junk, bad miters. They are off almost 0.025 from the top to the bottom.
I sent an email to dewalt and the response was take it to a service center.
Does anyone have a recommendation for repairs?
Thanks, abbey thomas

Try using actual squares for the alignment.

[Richard Coers]

A 12" Dewalt miter saw with a stock blade is wonderful for building decks, but not for precision boxes. If the Wixey is the type 2 with only 1 decimal place, it's not precision either. 0.1 degrees can make a huge difference. That means it can be .09 degrees off before it flashes to the next number.

[Art Mann]

Does 0.1 degree really make that much of a difference? Suppose you are cross cutting a 12 inch width plank. If the saw is 0.1 degree off, then the error will be approximately the cut width multiplied by the sine of the erroneous angle. In other words, the length of the error will be a little less than 0.021 inches. Is that really a "huge" difference? In most applications, I daresay the error will go unnoticed.

A 12" Dewalt miter saw with a stock blade is wonderful for building decks, but not for precision boxes. If the Wixey is the type 2 with only 1 decimal place, it's not precision either. 0.1 degrees can make a huge difference. That means it can be .09 degrees off before it flashes to the next number.

[Eric Danstrom]

Maybe it's time for a shooting board and a #5 handplane:
https://en.wikipedia.org/wiki/Shooting_board

[johnny means]

It's a construction tool. It's possible to get them dialed in real nicely, but at the end of the day, miter saws are engineered to a 2x4 standard. I opt for the table saw for any cuts that require real precision.

[Doug Dawson]

A 12" Dewalt miter saw with a stock blade is wonderful for building decks, but not for precision boxes. If the Wixey is the type 2 with only 1 decimal place, it's not precision either. 0.1 degrees can make a huge difference. That means it can be .09 degrees off before it flashes to the next number.

That saw is capable of work precise enough for serious woodworking, if you set it up right. It's the Wixey that's only fit for building decks, IMO.

[Jeff Bartley]

Abbey,

Try cutting two mitered pieces and check for 90 at the corner. Do you have a good square? Once those look good I'd cut four small pieces to form a 'picture frame'. Any inaccuracies will show up in the last miter as you fit the frame together.

As others have said a sled on a tablesaw might be the better method. Or a shooting board. But you can do it with your saw.

When all else fails you can always use shims (blue tape, paper, etc) at the fence to nudge the workpiece the last little bit.

Hope this helps.

[Robert Hazelwood]

The Dewalt 12" non-sliding miter saws are actually capable of very good accuracy IMO. I think something is off in the way the OP is setting up the saw- 0.025" is a huge error over 6" IMO, I bet a decent carpenter could freehand a better cut with a Skilsaw.

If the chop arm is nice and tight (mine is pretty good, only about 0.002-0.003 deflection when I try to make it wiggle, less in actual use when I am trying to chop straight), then the issue usually is the base and/or fence.

The biggest issue my saw had for accuracy was that the top surface of the rotating turret was a bit lower than the rest of the base, maybe 0.010" lower. This seems to be pretty typical, and makes it impossible to really dial in 90 in the vertical dimension, because the workpeice is unsupported at the blade and will want to tip down as the blade cuts. The solution is to make a custom zero clearance insert that is high enough to be at the same level as the base. A straightedge across the base should touch at each side of the base and at the insert. So when you place the workpiece on the saw it is resting on the base and the insert, spanning over the turret surface. I made my insert out of MDF and it is an improvement over the floppy plastic insert that came with the saw.

The fence on mine was pretty good in terms of straightness and squareness, but if yours isn't you can attach MDF faces and shim them with washers/tape etc until they are.

Once the base and fence are squared away, it is just a matter of dialing the blade angle in. I don't think a Wixey gauge is good enough. Just use a decent try square, or cut and flip method, or even a 5 cut method.

Also keep in mind that the face and edge of your workpiece need to be flat in order to get consistent results.

[Kyle Iwamoto]

I bet a decent carpenter could freehand a better cut with a Skilsaw.


I'm sorry. I would have to disagree with that. I would consider myself a decent carpenter. NOT a good carpenter. There is no way I could get within 1/32" of a cut every single time. 1/32" is bigger than .025". If that were true, the miter saw would have never been purchased, if any decent carpenter can get within 1/32" of a desired cut. That is about the thickness of a sharp pencil. Why waste money on a saw that is less accurate.

[Grant Wilkinson]

I had a similar issue with my Hitachi saw. That is, if the OP is talking about the bevel angle of the saw and not the miter angle. Some here seem to be assuming that his is talking about the miter angle. He says that his issue is with the vertical angle.

OP, can you clarify what you are talking about? If so, you may get some better advice on how to address it.

[ABBEY thomas]

I have done this.Thanks

[ABBEY thomas]

Art, my saw is calibrated. Square to fence and perpendicular to the base. I use both a starret square and a electronic wixey gauge to verify 90 degrees. As i bring the arm down( power off) and the gauge still on the blade, it starts going off perpendicular( 90 degrees). From 90 to 89.6 degrees. If you figure the tangent of that angle its a bunch. You can't cut a miter on a piece of cherry that's 5.5 inches tall for making a jewelry box.. There are adjustments for your miter and its locked after adjustment. The only thing that i can think is wear in the trunion housing( aluminum) and the steel pivot pin.when i mic them i don't see much difference. But, i don't know what they should be?
Thanks

[ABBEY thomas]

Ordinary compound, double miter 12 inch saw.

[ABBEY thomas]

That's what i am doing.
Thanks

[ABBEY thomas]

This has been very accurate for 10 years. I have tried latel 80 and 100 tooth blades.

[ABBEY thomas]

Wixey goes 2 decimal places. 100 tooth blade. Was one of the best saws going when purchased.

[ABBEY thomas]

I am cutting vertically for sides of a jewelry box. Miter. When i try to cut a bevel laying that 5'6 inch board flat, the same error.

[ABBEY thomas]

Don't know how.

[ABBEY thomas]

No, this is great for cabinet makers. I do agree a table saw is very accurate.
Thanks

[ABBEY thomas]

Good point.

[Matt Day]

FYI Abbey, we don’t know who you’re replying to in all those responses. I assume they are in order, but it’s difficult to know. There’s a quote button in the bottom right of each post and it will insert the persons response and you can reply below it.

[ABBEY thomas]

GRANT, my saw is calibrated. Square to fence and perpendicular to the base. I use both a starret square and a electronic wixey gauge to verify 90 degrees. As i bring the arm down( power off) and the gauge still on the blade, it starts going off perpendicular( 90 degrees). From 90 to 89.6 degrees. If you figure the tangent of that angle its a bunch. You can't cut a miter on a piece of cherry that's 5.5 inches tall for making a jewelry box.. There are adjustments for your miter and its locked after adjustment. The only thing that i can think is wear in the trunion housing( aluminum) and the steel pivot pin.when i mic them i don't see much difference. But, i don't know what they should be?
Thanks

[Ray Newman]

ABBEY t: you posted the saw was 10 years old. How much use has it seen? Your last post (#29) makes me think you probably are on to something when you wrote "the only thing that i can think is wear in the trunion housing( aluminum) and the steel pivot pin.when i mic them i don't see much difference. But, i don't know what they should be?"

[Josh Belleville]

Cut it a little long and use a shooting board to finalize the cut.

[Eric Danstrom]

Don't know how.
If this is in response to my post about using a shooting board, use the Google or go to the hand tool sub-forum, "Neanderthal Haven" and ask for help.