I assumed from your posts above you were talking about ripping a board to make blanks.
When you are making a rip cut (cutting along the grain) a band saw usually doesn't cut perfectly straight, but instead tends to cut at a slight angle. This is referred to as "drift" or more commonly as "lead". Rather than fighting this tendency, it is best to compensate for it by using the techniques described above.
In a cross cut, there will be no lead if the band saw is properly set up. I use a sled just as you are describing and is described in the files at the yahoo pen turners file section. I use it every day, and it cuts perfectly square.
If your cross cut is not square then your sled is out of square or the band saw is not properly set up. A dull blade isn't the reason you're not cutting square. Without seeing your set up, I obviously can't tell you which it is. I would suggest you go back to your owner's manual and fine tune the set up.
One common problem is have the blade guide assembly set way too high, and that can lead to the blade deflecting. Make sure the assembly is dropped down as close to the piece you are cutting as possible.
On my sled, I drop the assembly down to where the blank barely clears the underneath the guide block. I have a small wooden block that sits on top of the sled fence that contacts the guide block once the cut through the blank is complete and stops me from cutting farther. Another common problem is for the table not to be perpendicular to the blade. Use a small machinist square and check that.
Daleduts suggestions for making the sled will help you get the best cut possible, but you still have to be set up properly. I hope this helps.
I have played with different blade tensions as well as calibrating the bandsaw guides. Do you all have any ideas?[?][?]
