Help--I'm miter challenged.

[Ira]

49 years old and I never learned how to miter simple 45 degree corners.

I tried--BOY have I tried over the years--but if they ever came out half-way right, it was pure luck.

Let's say I have a 12 by 18 opening, and I want to frame it with trim. What size do I cut the lengths to, and how do I use the "box?"

I know this may be a tough lesson to give in a post, but man, it's about time I learned the correct way to do this. We didn't do much mitering while I was growing up in Brooklyn.

[Miriam C.]

Ira Dear
First be calm. Second get out your box and a good sharp back or box saw.
Third- If you have a 2" wide trim
on you 12 in Mark the 12 inch on only one side plus leave the width of your trim + 1" (you will cut this off with the miter) on the end. (both ends should be longer than 12" plus more than the width of the trim.)
Put the marked side against the inside of your box. At the 45 degree slot.
Be absolutly sure you have two short sides and two long sides.
Got that. Saw! Your miter box should have slices on both ends so use both ends and you will get it right.
Use practice wood and check your kerfing. (width of wood the saw removes)

[Ira]

Ira Dear
First be calm. Second get out your box and a good sharp back or box saw.
Third- If you have a 2" wide trim
on you 12 in Mark the 12 inch on only one side plus leave the width of your trim + 1" (you will cut this off with the miter) on the end. (both ends should be longer than 12" plus more than the width of the trim.)
Put the marked side against the inside of your box. At the 45 degree slot.
Be absolutly sure you have two short sides and two long sides.
Got that. Saw! Your miter box should have slices on both ends so use both ends and you will get it right.
Use practice wood and check your kerfing. (width of wood the saw removes)

Okay, Miriam--let me see if I understand this. I'll try this using different measurements--15 long, 3" wide trim.

No, wait. I still don't understand.

Am I pitiful or what?

[halfdome, Danny]

Ira, One thing to keep in mind is that a square or rectangle has 360 degrees just like a circle. Example: 4 x 90 deg = 360 deg. or 8 x 45 deg. = 360 deg. If you cut a 44 degree cut on one of the corners you have to make it up on the other mating piece with a 46 deg cut or it won't add up to 90 deg. & you will have gaps in your joints. Danny

[Miriam C.]

Ira you are normal. If it was the easiest thing to remember furniture makers would go out of business.

15 inch finished and 3 inch wide board = 1 inch + 3 inches + 15 inches +

Mark 4 inches up the board and then make your second mark 15 inches from that mark.

If it helps you remember where your short sides are, Make another mark 4 inches from the 15 inch mark.

With the short side of the board closest to you:
Draw a diagional line three inches from both of the 15 inches going in different directions. Mark to the top end of the board, then on the other side of the 15" mark do the same. If you have a short side and a long side you have it right.

Cut on your line so the line is just a trace

[Ira]

Thank you, Miriam!

That extra 1" thing kind of threw me. lIke, how can it always be 1", regardless of length and width of trim?

Must be one of those complicated math things that I failed in high school, like pie:

I could never extraploate it past 3.1!

[An Ol Timer]

Ira,
You get that down pat and then we'll start you on your next lesson.

Compound Mitering 101 :lol:

[Miriam C.]

The cheaters way
Take two of your trim pieces and make a cross close to the end of one board. Be sure it is square.

Draw a line on both sides or the board.

Move down the board 15 inches from the second mark.
Lay your trim in a cross again.
Draw a line on both sides of the board

make a diagional line from one corner to the other.

Be sure you have one short side and one long side
cut the diagional lines only

[Miriam C.]

I always add the 1 inch so I get a good clean cut. That is the only reason if you are making a simple 45Degree cut.

Compound mitering. I really have to think those through.

[DestinDave]

Wait till you graduate to crown molding Ira.. Those you cut upside down and backwards...

[Ira]

Wait till you graduate to crown molding Ira.. Those you cut upside down and backwards...

I'll probably wind up doing the same with MY molding, even though I'm not supposed to.

[rainjer]

It all depend on if you are doing the trim around the window or inside the window opening. My diagram below assumes around the window & using 3" trim. I like to lease a 1/4" reveal around the window. It is not required.

If you have a 12" opening, & want a 1/4" reveal, your material cut length wold be:
12" + 1/4" + 1/4" + 3" + 3"+ 18 1/2". I would rougn cut to 19".

Your 45 deg. miter would be 12 1/2" from the short side to short side.



If you are doing the inside, to would be 12" long side to long side.

[Krob]

Thank you Ira, I know I would have been asking that question myself real soon.

[Miriam C.]

Rainjer wrote:
If you have a 12" opening, & want a 1/4" reveal, your material cut length wold be:
12" + 1/4" + 1/4" + 3" + 3"+ 18 1/2". I would rougn cut to 19".

Should read 12" + 1/4 + 1/4 + 3 +3 = 18 1/2 inches.

Its that shift thing with the + and =.

Ira are you doing the cabinettes or windows?

Ira and Krob (All ) remember kiss or go to Home Depot and check out thier classes. They are short and to the point.

Enjoy
Miriam

[rainjer]

Rainjer wrote:
If you have a 12" opening, & want a 1/4" reveal, your material cut length wold be:
12" + 1/4" + 1/4" + 3" + 3"+ 18 1/2". I would rougn cut to 19".

Should read 12" + 1/4 + 1/4 + 3 +3 = 18 1/2 inches.

Its that shift thing with the + and =.

Thank-you. I was in a hurry at work & did not see my mistake.