I'm about to flip. Today was the day to lay down the floor. All is well until I go to cut my 45* miters. First problem is cutting 45* miters with my trusty 10" miter saw. It won't do it - 5" plank is too much for a 10" saw to cut a 45. Darn! So off to big orange to get a 12" saw. I get home and things aren't going together right. I'm getting wierd gaps. I look closer, and hold my cuts up to a straight egde and I find the problem - my cuts aren't straight. Now had someone asked me to cut a non-straight line with a miter saw, I would have told them they were nuts. But it has happened. The cut is a very slight radius, with the center of the cut sticking out further than the ends. This causes my miter joints to be tight in the middle, with gaps on both ends. Totally unacceptable to my perfectionist butt. My 10" saw has served my for 5+ years without seeing this. The 12" did it right out of the box.

Anybody know what's up? Ever seen this? Know how to fix it? Am I doing something wrong? I figured out how the saw could do this if it was made wrong. If the pivot axis isn't parallel to the axis of rotation, then it would push the saw though the board with a slight sideways inclination. I don't have my precision instruments here at home to see if that is the case though. I did check 2 different blades and varied my feed speed and none of that helped.

I'm stumped. I don't want to return the saw if I'm doing something wrong, but really - how do you use a miter saw wrong? Hard to do. Help!

Are you using a roller stand or something for support. If the board is not laying perfectly flat on the saw table it will not correctly, clamping it down may help. Also could be the blade flexing if it is a real hard wood. If that don't work consider a lap joint (aka) log cabin joint.

No roller or stand or anything. Saw is sitting on the floor and I'm holding the wood against the table and fence by hand. It is an engineered 1/2" board with an oak top. Nothing too crazy.

I'd rather just cut good miters than change the design.

Grrrr....

Hmmm.... are the boards pretty straight? Or are they slightly cupped??

I know this is too little too late but your problem is the blade you are using either it is dull or the wrong blade for the job. More teeth equal better and cleaner cuts.

The boards are nice and flat across the width of them. If I lay one on the ground, they bow up a wee bit along the length, but they are easily flattened with very slight pressure.



I tried both the all purpose blade that came with the saw and a nice 80 tooth carbide finishing blade. Same results with both.

Take that Delta back Dave and get a better miter saw .

Good guess, but my 10" is a Delta that I've been happy with. The offending 12" is a Ryobi...

Take the 10" and cut the board. Flip it around and line it up by sticking the blade into the cut the other way. As you cut slightly push towards the blade and go slow downward.


Mark the board completely across on a 45 with the speed square and see just what's happening as you cut downward slowly.

Well, the solution is kind of a PIA, but it's working. I borrowed a DeWalt radial arm saw from my dad and I am using it to cut the mitered boards. It works though, and I now have nice tight corners.

Yep, the problem was crappy chinese tool and crappy blade. The low end Delta bench tools are made in China and are known to be a pos.

Yep. Crappy tool. I can grab the head and twist it and induce a 2-3 degree twist in it with very little effort. Grrr....

yea, it's too bad. At one time, Delta was known to be high quality tools but that was many years ago. I suppose some of their high end cabinet shop grade are still ok but do not compare with the best anymore.

Trade it for the 10" makita sliding compound miter saw. Works great with a fine tooth blade for the miters. It will cut up to almost 8" on the 45*. Wel worth the $. Best deal I found was on Amazon.com about $60.00 less than depot with free shipping.

Hitachi and Dewalt are fine tools as well!