miters and bevels and measurements

[wreckwriter]

This is confusing me, I hope I can explain it well enough that someone will understand my question.

OK, I need to cut a 45 degree bevel across one end of 18 1x6 pine boards. I plan to do this with a CMS. My question involves measuring and setting up for the cut since the blade will hit what will end up as the short side first rather than hitting the side which will be the final length of the board...

Someone explained to me that on a 45 degree miter the difference between the long side and short side would be the same as the width of the board. Does this work with bevels too? In other words, if the board is 1/2 inch thick and I bevel the end at 45 degrees, is the difference between the sides going to be 1/2 inch?

So if I want to end up with a 3' 8" board I would start my bevel cut at 3' 7.5". Is this right?

Thanks for your patience with a guy that never quite got math and angles and such..

[bigsteel15]

Your math looks right to me.
A 45 deg angle has equal straight legs.

[wreckwriter]

Thanks much

[LarryG]

Your arithmetic is correct. However ...

My question involves measuring and setting up for the cut since the blade will hit what will end up as the short side first rather than hitting the side which will be the final length of the board.

You can get around this, assuming sufficient clearance exists, by moving the workpiece to the other side of the blade and flipping it (the workpiece) over.

Either way will work. Main thing is to not lose track of which side is which. And toward that end, although one can do the arithmetic and make the appropriate compensation, when cutting miters or bevels I always like to make my pencil mark on the same side I measure. That may be the long, or it may be the short; either way, I take a measurement and transfer that directly to the workpiece "as-is" and let the other side of the miter/bevel take care of itself. Taking the original measurement is one possible place to make an error; measuring the place the mark is a second; doing arithmetic, however simple, just introduces a third.

This is another instance where cutting long and "sneaking up" on what you actually need is generally good practice.

[wreckwriter]

moving it to the other side.............. Why didn't I think of that! Thanks Larry!

I agree about sneaking up. My plan is to get one piece perfect and then just set the miter saw stand rails and blocks to do the others. Getting them all the same is most important.

[Popeye]

Another thing to note.....If both ends are to me mitered then the total length of the long side will be the length of the inside plus twice the thickness/width of the board. Pat

[wreckwriter]

Another thing to note.....If both ends are to me mitered then the total length of the long side will be the length of the inside plus twice the thickness/width of the board. Pat

Good point. This was just one end mitered though. 20 boards, all came out great.

[Popeye]

Good point. This was just one end mitered though. 20 boards, all came out great.

Super, glad it worked out. Pat