45 degree table saw cuts are curved,...

A little suggestion.

Go to Library, get copy of Fred Bingham's book, Practical Yacht Joinery.

Tells you how to build a jig that produces dead nuts 45 degree miters every time.

It's a no brainer.

Lew

The wood could be sliding on the miter gauge toward the end of the cut?

Sounds like it could be a loose track, too.

Roy

And a little sandpaper glued to the miter gage can work on some... Then=20 the wood won't slide.

The sandpaper allows the wood to grip better. Then you don't usually=20 have to clamp the wood.

--=20 Will R. Jewel Boxes and Wood Art

If it's a contractor's saw, then you're blade is getting out of square when you tilt you. Common problem with a contractors saw. Best thing to do is make a jig as suggested earlier.

An old saying from my father: "Let the tool do the work." [He was showing me how to use a hammer for the first time. He could use one all day long without tiring.]

Blade not sharp? You are possibly bearing down too hard when passing the wood through the saw. The stress eases at the end and you naturally then shear away.

Make sure: Sharp blade [carbide?], right strength motor, right size pulley for rotation speed. Then ... *some* pressure to direct the wood, but ...let the tool do the work as you do enough only to guide it. Same thing with sanding, chiselling, ...anything.

I like this one!

Hey, Lew.... have you had a chance to compare Bingham's new(er) book? Boat Joinery and Cabinetmaking Simplified.

Rob.

That's the one I have, just don't remember the title as well as the old one.

Lew

As others have suggested you might check that the blade is still square when you tilt it but there might be another cause. Is your workpiece 'above' or 'below' the cut?

As a general rule, one should try to cut so that a slight slip in the workpiece simply causes the error to be on the fat side, rather than the 'thin' side. In this case, it means that the waste should be on the underside of the tilted blade so that if the workpiece lifts slightly while working it through the blade, the edge will be slightly fat and a second pass can easily trim off the excess.

There are lots of reasons that the workpiece could lift - poor handling, the board warping due to heating of the cut, etc. As others have noted, a TS is a precision tool because it pulls the workpiece against the rigid top surface. However, when you have the blade tilted at such an extreme angle the downward forces are reduced quite a bit and other forces (for example, you are actually cutting 40% more wood than the thickness of the material) tend to dominate.

A final possibility is that the blade is actually lifting (due to wear or poor saw design) as you bring the workpiece through the cut. This obviously doesn't affect you if the blade is set to 90 degrees and it is a through cut but it will cause problems if your blade is tilted. One way to check this is to run a 3/4 inch dado blade set at 90 degrees. Set the depth to a precise amount with the blade stationary and then run a piece of scrap through (preferably hardwood) and see if the cutting depth is actually deeper.

Some ideas to check... TWS