I was making several frames last night, when disaster almost struck. I got all the wooded ripped to width routered them and cut the miters. It was going real smooth until I went to put them together. The miters on the last corner didn't meet when I tried putting them together. I was freaking out I spent all that time setting everthing up so they would all come out the same that worked, to bad it was wrong. I checked my miter saw and it appeared to be set at a 45 degree angle, upon further inspection there was a small piece of scrap keeping it from locking completely into the 45 position.
Luckily I was able to trim all the angles to a true 45, but I also had to trim all the pieces to be framed down about an 1/8". I got them all completely built after about an extra hour of work. So from now on I'll check the miter alot closer.