mitered doors

[John Teichman]

i am changing some cabinet door i want to miter the frames what is the best setting is it 45 degree or should i be looking at maybe
45.5 degree angle seems like 45 is not a nice tight miter?? sanding it a lot to get it tight.

[Jamie Buxton]

45.0 degrees is what you need. However, the calibration of your miter gauge or chopsaw might be a little off. Perhaps you must set it at 45.5 degrees to cut at 45 degrees.

[Sam Murdoch]

Yes, less sanding and more time dedicated to adjusting your tool. 45° is what you want.

[Jamie Buxton]

One more possible issue: maybe your saw is not making a straight cut. If the blade is a little dull, it deflects sideways when it hits the leading edge of the plank (which is at 45 degrees from the blade). After the blade gets fully buried in the wood, it un-deflects, but it takes some distance for it to do that. The result is a cut that's curved. It isn't curved very much -- maybe 10-20 thousandths -- but if you put two of those curved cuts together, you see a big gap.

[Mel Fulks]

For the 45 degree to work perfectly the material needs to be perfectly straight. I suspect that the factories might have to touch up joints on a floor stand disk sander,especially since they are useing moulded stuff. Adjust the saw perfectly ,then you might have make fine adjustments with plane ,sander ,or chisel. A structural mitre is a lot different from decorative on stable plane.

[Joe Hillmann]

Depending on how many you are doing it may be easier to build a sled for your table saw to get perfect 90 degree corners. Here is one I built.
265295

It is just a 90degree corner glued to a table saw sled at close to a 45 degree angle with the point lining up with the blade. Using this method the only thing that matters is that the corner is a perfect 90 degrees. Then as long as one side of the joint is cut to the right of the blade and the other is cut to the left of the blade you will end up with a perfect right angle when you glue your frames together.