WTF??

Here is saw:


Here is problem:


Where did I go wrong?? Trying for 9" ID square. It's easy to butt pieces square, but 45* cuts are kicking my ass with 5.5" wood.

Go over to woodworkingtalk.com and join the forum. There's a huge group of fine woodworkers there that will have similar equipment and can get you fixed up. I don't have a miter saw.. all my miters are done on a table saw with a saw sled.
Best luck..

The cut is not exactly 45*. If it's a detent point, there should be an adjustment somewhere. The crosscut guide for my table saw is like that. I have to set it with a protractor.

Pieces need to be IDENTICAL length, check saw with a speed square to confirm 45 is really 45....

You need to adjust the chop saw using a square first. It should be cutting perfect on a 90* & 45* straight and compound. If the saw is set up perfect then it is user error. Make sure you are cutting on the outside of the line at both ends & not just cutting down the center of your mark... Always account for the thickness of the blade.

"Tune" up your saw.


Double check your detents for miter and bevel.


Every new saw I buy, I take a minute and go through all of them.


You'd be surprised how far some of them are off, and they all are off.
Also, back cut your 45s ever so slightly, half a degree or a tad less, so the top face of the 45 hits before the bottom.


Once the saw is perfectly setup, you may consider cutting all four pieces together in a "pack" to make them identical.

If you do this, leave out the backcut angle though.


Good luck.




 

You gotta cut on the right side of the line.....or left, whichever.

Meh, close enough!

make a 45 deg cut.   Take the two pieces, flip one over and assemble them such that they form a 90 deg angle.    Use a GOOD square to measure the angle - are they 90 deg?     adjust as needed.

Make sure each side of the frame is EXACTLY the same length.    Might want to make a stop block on saw to ensure equal lengths.

This kind of work is where you suffer from cheap tools.

Practice, practice, practice

Nice grouping.

As others have said in verifing lenghts of your picture frame sides. Most of the better saws have the ability to adjust the detent/stops and yours may need that .

It's been covered pretty well.
But to recap, in order to get perfect miters, EVERYTHING has to be perfect. Errors usually add up rather than cancelling each other.

1. Stock must be straight; plane or joint the edges until they are straight and parallel.
2. Saw must be set to exactly 45 degrees for the cuts you're making, and perfectly 90 degrees on the vertical.
3. Blade must be sharpened correctly and stiff enough to prevent wandering in the cut, especially so in tough or knotty hardwoods. I avoid thin-kerf blades for precise work for  that reason.
4. All stock pairs must be exactly the same cut length (Top rail must match bottom rail, left stile must match right. Use a stop block clamped to infeed table if you must.
5. Blow sawdust from fence and table between cuts to allow stock to register tight against them.
6. Hold stock solidly while the blade is cutting; clamp it down if practical.
7. Hold side pressure the same on each cut; a little sideways push toward the right or left on the saw's handle affect the angle to a very slight degree.
 Keep it consistent as you setup the saw's angle stop, and again while sawing.
8. If you  simply cannot avoid having a miniscule error, keep it short at the heels rather than the toes of each cut.  Very small gaps are not as obvious at the inside corners as they are on the outside.

Edited to add: One more thing to consider:
Your stock must be kiln-dried to a level appropriate to your local climate. If you use green or unseasoned wood, even if you get perfect miters, they will shrink apart in a year or two when the wood dries, especially on wider frames.
Narrow picture frames less than 2 inches wide?-not so much.

It's the saw, I have the same one, the detents for all angles are off.  I double check with an angle finder every time now, the fence on the saw fucking sucks whale shit and is a bitch to cut crown nested.

Most likely the detents.

But also check the blade and bearings. Any problems there will create different lengths. Even if your stops and set up procedures are perfect. Cutting slower(feeding blade into wood) will help a ton in getting more consistency as well.

And use a stop for your length.

nothing like trying to hand measure and hold for each cut to get you slightly off for each cut.

Least expensive method to solve your problem (based on a square frame.  ie all four boards being equal in length)
-go to the local hobby store and pick up a large plastic drafting triangle.
-move the saw to the right at 45 degrees, lock the saw blade in the down position
-adjust using the drafting triangle (see owners manual)

Your boards are too long to use stops on that factory fence.  You need to install a long piece of wood to your fence to extend it. (note the holes in your aluminum fence).

Mine is a bit more advanced but I think you'll get the idea.  (note the stops on my fence)


-OK, take your four new boards and cut a miter on each board.
-take one of the cut boards and flip it over.  
-line it up on your saw to cut the opposite miter (no cutting yet)
-clamp a scrap piece of wood to your extended fence so that your already cut miter butts up against it.  Clamp it TIGHT so it will not move.
-now take each board, slide the already cut miter against your stop and cut the opposite angle.  Yes this includes the first board as you might have clamped your stop a little bit off from where you lined it up with the saw blade.

If you've done the above correctly, all four miters should line up nice and flush.  Note, this is an end grain to end grain joint so you want to reinforce it with something other than just glue.  Dowells, biscuits, nails, splines, etc.  Best way to clamp it up is with a band clamp.  

Or you could build a sliding miter jig for your table saw but that's another lesson.

"Can't see it from my house!"

Make sure to check the drafting triangle for square.  The last one I got was horribly out.

And the most expensive method to solve the problem:

Just glue it.  Doesn't have to be perfect.  

Homer Simpson making the spice rack comes to mind..

I thought that was an expensive or good saw?

I'll block them later. How do I fine adjust that saw? It just had a rod that fits into slots in the base.

You'll have to find your owner's manual.  
You'll need to losen up the stop that halts the saw at 45 degrees
then there should be some kind of adjustment screw / bolt you can turn

It is a great saw... Same goes for the delta table saw, but any professional saw will need adjusted to work perfect.

Yep, I've only ever seen one that didn't need to be adjusted from the factory.  

And the Makita is a damn good saw.  

Here's a great article on tuning your saw:  http://www.thisiscarpentry.com/2010/07/23/miter-saw-tune-up/

And TiC has a bunch of other great articles.  Definitely worth your time to browse around.