# how do I get PERFECT 45 degree angles



## agrandfathers_legacy (Aug 17, 2015)

I am trying to get perfect 45 degree angles using my miter saw. I cannot use a jig for the table saw because I am using a work site portable table saw and it does not have miter track on it. My miter saw says its on a 45 but they are still off. I have checked the rails and guides and it all seems to be square but once I swivel it to the 45 its still off. Anyone know what else I can use to make perfect 45's.


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## GeorgeC (Jul 30, 2008)

Does your saw set 45 degrees by a detent or by friction?

If the 45 degree position can be varied then buy a 45 degree drafting triangle and set the saw by this. If your saw will not hold this position then you have a saw problem.

If the position is set by detent then you have to adjust your fence to the 45 degree position using the same triangle.

George


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## woodnthings (Jan 24, 2009)

*use a draftsman's triangle*

Set the triangle or a speed square against the fence and the blade to accurately set the miter angle. Adjust the miter head or the fence, if it doesn't fit precisely. Use a sharp blade. A dull blade will not make an accurate cut. Put sandpaper strips on the fence to prevent the work from creeping as you make the cut. 

Make the cut, then flip one piece over and mate it to it's other piece. Lay a straight edge along them both. There should be no gaps and they should form a straight line. That's how you check the miter angle. :smile:


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## woodchux (Jul 6, 2014)

Great advice from previous posts! Many miter saws & TS do show the blade is set at the 45 degree stop, but best to first check by cutting a scrap piece, then use the method as described by GeorgeC & woodnthings to adjust and check again. Be safe.


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## MattS (Feb 17, 2010)

woodnthings advice is spot on!

Use a drafting square to set the blade to exactly square to your fence - and remember that the teeth of the blade cause a slight offset so you need to avoid bumping into them. Cut a piece, flip it over and see if cutting a sliver off it results in a perfect square. If not, you need to adjust more. Check from both sides of blade if it's still not working, you may find that your fence isn't straight (I've had one get bent concave, so there was no way to easily square it).

I've gone through a few miter saws over the years, once one is out of square (whether due to fence damage, locking mechanism or measurement lines) they are rarely worth fighting with. Either get it adjusted to perfect square and leave it there, or make it your rough cut saw and get a new one for finish work. 

Frustrating stuff, sorry to say :sad:


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## Ghidrah (Mar 2, 2010)

That has a better chance of working if one is just chopping down, if one is using the slide to make the cut it may still end up + or - 45°


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## FrankC (Aug 24, 2012)

Two things, an accurate saw and the material not moving during the cut, so check your saw and clamp your work.
A common problem when making a four sided object, picture frame or box, is that the two opposite sides are not exactly the same length, so the miters appear to be off.


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## NickB (Sep 24, 2013)

Also be aware that the user _can_ deflect the blade as well. If you grab the handle and push it to the left or right, you'll see that you can easily change the angle by a degree or so. If you're doing this while cutting, _you_ may be throwing the angle.


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## 2lim (Aug 30, 2009)

One more thing: If you are making a frame, make sure that your pieces are EXACTLY the same length. If you are trimming a house, cutting on a 45 only works if the corner in the house is actually 90.

Simon


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## Nick Sandmann (Oct 24, 2014)

Hand plane and a shooting board.

Not sure what you're making, but for furniture I use a shooting board setup to make 45 degree cuts. I cut the board very close to length using whatever(chop saw, table saw, hand saw, etc...), and then use the shooting board to get it exactly to 45 and trim to the final length.

On the flip side, if you're just installing crown molding in your house, just get your saw adjusted as listed above and you should be good to go. If you're doing furniture then I stick by my shooting board suggestion.


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## TimPa (Jan 27, 2010)

if you are making frames, you don't need a perfect 45 degree as much as you need them to combine to make a perfect 90 degree corner. most miter saws will do this if you make one cut from one side, and the mating cut from the other side of the saw.

if you are wanting a perfect 45, keep adjusting your table and checking the cut board until you are happy with it. your manual should also help you with the adjustment.


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## EdS (Mar 21, 2013)

If your saw is not cutting the 45 degree angle correctly, using the positive stop, it most likely isn't cutting a 90 degree accurately either. If your miter saw is like most, it has the bracket on the front with the degrees market on it and also has the slots which are used for the positive stops. This bracket is adjustable on most saws. Try this, loosen the bolts that hold down the bracket, get a good square and set the blade to 90 degrees, lock the blade at this position then adjust the bracket to match the 90 degree position and tighten the bolts back down. I bet the saw will then have the positive stops in the correct position for all the angles, not just the 45 position.


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## FrankC (Aug 24, 2012)

It is not always cutting the perfect miter but getting it assembled to look like the perfect miter. 
An old contractor trick when framing around doors and windows is to lay a flat carpenter pencil at the outer edge of the miter saw table to raise that end of the board up a bit so the miter is undercut on the back by a degree or two.


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## woodnthings (Jan 24, 2009)

*good tip!*



FrankC said:


> It is not always cutting the perfect miter but getting it assembled to look like the perfect miter.
> An old contractor trick when framing around doors and windows is to lay a flat carpenter pencil at the outer edge of the miter saw table to raise that end of the board up a bit so the miter is undercut on the back by a degree or two.


Another trick is to keep a few business cards to insert behind the stock to pull it off the fence just a bit, either near the cut or at the opposite end to just slightly change the angle instead of messing with the arm adjustment.


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## Steve Neul (Sep 2, 2011)

What helps with miters more than anything is a very sharp blade. As soon at the blade gets a little dull on my saw it wanders all over.


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## FrankC (Aug 24, 2012)

woodnthings said:


> Another trick is to keep a few business cards to insert behind the stock to pull it off the fence just a bit, either near the cut or at the opposite end to just slightly change the angle instead of messing with the arm adjustment.


It is usually better to manipulate the stock than change the setting, particularly when it is moved so little so as not to be noticed if it is not immediately set back to normal. DAMHIKT


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