# Thread: Need help with miters

1. [OP] Member
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## Need help with miters

How do I measure a board if I am cutting angles the ends? Its easy enough to measure for a 90 deg angle. Just measure out from the blade and cut, but I cannot figure an easy way to measure for a 45 deg angle. In other words, if I want to make a picture frame, what is the procedure for measuring the boards and cutting them. If I am missing some minor thing here, please forgive me for being so thick. By the time I get through trying to get these cuts right my picture is like half the size I started to make.

2. Bruce, there are different ways, the simplest is to just draw it out full scale if you are having trouble wrapping your head around it. Otherwise, you need to know the rebate size desired, the internal size, and the width of the stock. Geometry from there.

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What Steve said. Either draw it in SketchUp, et al, or lay it out full size on a piece of paper. From there it's "just" a matter of cutting 2 boards each to the same exact length with 8 perfect 45's.

John

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The length of the outside edge is the length of the inside edge plus 2 X the width of the piece. For example. If I want to make a picture frame for an 8 X 10 picture. The pieces I am cutting are 2" wide. I will use a 3/8" rabbet for the picture to sit in the frame. I will need two pieces 13 1/4" (10" - (2 X 3/8") + 4") and two pieces 11 1/4" (8 - (2 X 3/8") + 4")

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I run my rabbet first. Then using two pieces of stock laid back to back (rabbets facing out on both pieces) place tape measure on the inside edge of rabbet with actual size of desired opening, plus 1/8th inch. Where tape meats rabbet on other piece gives me exact length to cut pieces.

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Originally Posted by Bruce Wrenn
I run my rabbet first. Then using two pieces of stock laid back to back (rabbets facing out on both pieces) place tape measure on the inside edge of rabbet with actual size of desired opening, plus 1/8th inch. Where tape meats rabbet on other piece gives me exact length to cut pieces.
I don't follow this at all.

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8. Do you already have the picture mounted?

You could work directly off that.
The critical dimension is the "shorter" side of the miter that meets the picture.

If you make a mistake - it could be cut down for one of the smaller pieces.

Take the framed artwork and place it on a stable flat surface.
Trace around the outside.

Put the original art safely away.

Each molding will have a relief cut away (the side that holds the picture) that is a fixed distance
in from the inner dimension - 1/4" or more.

Inside the tracing made of the mounted artwork, trace a second line that distance IN from the template line.
That's where your molding should line up, when properly fitted.

*********

I cut with a miter box, by hand.
I cut the first three, fitting to the actual mounted artwork or cover glass.

I leave the last two pieces long, and overlap them at the final corner.
I cut directly through these last two for the final joint,
to correct for alignment errors.

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## Think I figured it out

Thanks to everyone for the good advice, I think I figured out what I was doing wrong. My problem was more like I just didn't where to start cutting even once I knew what lengths I wanted. After seeing everyones formulas and such, I got to thinking. And I just now realized that I was not allowing for the width of the kerf when I made the cut. Does that make sense? I should have figured this out before posting I guess.
Bruce

10. Originally Posted by Bruce Golling
And I just now realized that I was not allowing for the width of the kerf when I made the cut. Does that make sense? Bruce
Perfectly.
Were you cutting all the pieces, in advance - then coming up short?

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Originally Posted by Jim Matthews
Perfectly.
Were you cutting all the pieces, in advance - then coming up short?

Yes that was one problem. And then I believed those knuckleheads I went to school with who said to not worry about geometry because we'll never use it. Once I just sat down and looked at the hyptotenuse and general geometry it became a lot clearer. I thought for a minute I was going to be to only use pocket joints.
Anyway I think I'm on the right track, thanks again everybody for enlightening me.
Bruce

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