# miter saw not cutting square



## jdfnnl (Apr 10, 2017)

I've got this DeWalt 12" sliding miter saw I've been using to do a corner miter with some clear cedar siding. The work is stain-grade and so the cuts need to be very accurate to avoid the result of gaps. Problem is when I am cutting these 45's with the stock standing against the rear fence, the cuts do not turn out square to the bottom edge across the face of the boards. As such I have been getting by until now by drawing a square line then inching the overhead bevel about a degree to either side on each cut an then inching up to the cut line as the angle looks right. 

Needless to say, this is way more tedious than need be and after thinking about it enough, it seems likely that the rear fences are not reliably square with the table of the saw; the saw is currently at the job, so I am not able to verify this now with a square, but my question is, if this is the case, is there a way to re-calibrate the rear fences square with the table with some saws, or is the saw now effectively useless for this operation?


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## TheConstruct (Dec 8, 2017)

You should be able to adjust the fence to square it to the blade. Find a pdf of your saw's manual online and you'll know for sure.


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## Xtrememtnbiker (Jun 9, 2013)

This should help.

http://www.thisiscarpentry.com/2010/07/23/miter-saw-tune-up/


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## Deckhead (Dec 9, 2010)

What blade are you using too? A good blade will stop a lot of deflection in some sliders.


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## Tom M (Jan 3, 2007)

My old DeWalt has two bolts on each side of the pivot handle that I would loosen up to free the connection.

From there square it up with the blade dropped. On my Makita the bolts are behind the fence itself.

On both units the bevel is adusted by on the sides of the vertical pivot


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## Leo G (May 12, 2005)

jdfnnl said:


> I've got this DeWalt 12" sliding miter saw I've been using to do a corner miter with some clear cedar siding. The work is stain-grade and so the cuts need to be very accurate to avoid the result of gaps. Problem is when I am cutting these 45's with the stock standing against the rear fence, the cuts do not turn out square to the bottom edge across the face of the boards. As such I have been getting by until now by drawing a square line then inching the overhead bevel about a degree to either side on each cut an then inching up to the cut line as the angle looks right.
> 
> Needless to say, this is way more tedious than need be and after thinking about it enough, it seems likely that the rear fences are not reliably square with the table of the saw; the saw is currently at the job, so I am not able to verify this now with a square, but my question is, if this is the case, is there a way to re-calibrate the rear fences square with the table with some saws, or is the saw now effectively useless for this operation?


The fence needs to be square with the deck. The sawblade need to be square with both. When you spin the saw to either miter it also needs to remain square. All sound simple and it should be, but lots of times it's not.

Your stock needs to be flat also. If it has a cup in it there will be problems getting a straight square cut.

As a quick temp fix, if you find the fences not square with the base, you can put tape on the top or bottom of the fence where the board hits to "square the board up". Finish up your job that way and then you will need to figure out what is wrong with the saw. Sometimes you need to shim the fences with paper to make them true. Sometimes things are so screwed up you can. Bent or warped castings can interfere with a perfect cut.

Get out the machinists square and start checking out squareness relative to blade position and fence position. You'll find the issue, if you can correct it is another story.


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## tjbnwi (Feb 24, 2009)

If it is beveled siding you have to adjust the saw setting for the compound angle. 

Your issue is not unusual with that siding. Try the saw with flat material. 

Tom


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## sunkist (Apr 27, 2012)

I just use my speed square stood up and layed down, cutting stock stood upright can have its problems, if its a hard wood you may be getting blade deflection which can get worse the smaller the trim cut,


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## Leo G (May 12, 2005)

Sometimes the stock moves a bit too.


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## Morning Wood (Jan 12, 2008)

I agree. Get out the square and start checking things. You can probably download instructions for the saw to tune it up if you even need them. Sometimes wood just sucks though.


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## Justin Huisenga (Apr 10, 2013)

If all you are adjusting is around a degree it sounds like a fence not square to the table. Pretty common and DeWalt saws have the sub fence bolts all the way at the outside edge. They can warp over time if you do a lot of cutting in position. 

I stiffened that area of the saw by drilling and tapping a hole through the casting of the sub fence close to the blade for an 8-32 machine screw. The screw will both take the flex out of the fence and push forward a fence that out of square.


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## Robie (Feb 25, 2005)

Leo G said:


> Sometimes the stock moves a bit too.


It's amazing what can throw a cut off a little...small chip of wood under the stock or between it and the fence....stock originally not square, etc, etc, etc...


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