Replies

1. 
   seeyou | Oct 12, 2008 01:21am | #1

   You need two different crown profiles or a wedge on the rake side.

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2. 
   seeyou | Oct 12, 2008 01:22am | #2

   Or change the spring angle.

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3. 
   rlrefalo | Oct 12, 2008 01:32am | #3

   Like seeyou said, two crown profiles is the traditional way. Not done very often any more. I have a diagram showing the method of figuring the modified rake profile , I could try to post it if anyone is interested.

   Rich

1. 
   Henley | Oct 12, 2008 02:00am | #4

   I've seen that before, but it's been a while.
   If posting isn't to much of a pain I'd like a refresher. Something about transcribing the defining points into a
   straight edge then pivoting the straight edge to the desired pitch,
   right?

1. 
   rlrefalo | Oct 12, 2008 07:12am | #9

   Henley, the diagram I have is very similar to what Moogie posted.

   Rich

4. 
   AitchKay | Oct 12, 2008 02:13am | #5

   There are three ways that I know of:
   1)
   Use a standard crown on the fascia, and a custom-made, elongated profile on the rake.

   2)
   Tip the fascia crown out more, and see how it looks. You can often get away with this on a lower-slope roof, and it’s worth looking at even on a 12/12. Cut normal outside miters on two scraps of crown. Hold the rake crown in its correct position, and match the fascia crown up to it. The fascia crown will be tipping WAY out, but it often looks just fine. A backer block is usually a good idea, since the fascia crown does not sit on its back-flat, only on a point. And, of course, you have to leave enough roof sheathing hanging out to cover this over-extended crown.

   3)
   Miter the fascia crown as if it’s a normal outside corner. Miter a short scrap to meet the fascia and turn the corner onto the rake, but keep this scrap DEAD LEVEL to match the fascia miter -- forget about the rake angle at first, and just fit it to the fascia. Now miter the other end of the scrap to meet the rake. To do this, press the bottom/”wall” back-flat against the table of your chop saw, and the top/”ceiling” flat against the fence. Set your saw to 22 1/2 degrees (half of the 45 degree, 12/12 angle) and make your cut so as to come to a point right at the top edge of your short scrap. Now cut the main rake crown at 22 1/2 degrees to match, and continue up the rake.

   The deal is that you can only miter a molding in one plane at a time while still keeping the same profile. So you split it up into two separate tasks: miter around the fascia corner, usually 90 degrees, and then miter from level to rake, which varies according to the pitch of your roof.

   This same rule holds when trimming stairs, by the way.

   We often don’t have to deal with this because we use flat stock so much. With flat stock, we could follow the process in 3) above to make up for the elongation problem, but it’s easier to just clip off the protruding corner of a flat board, so that’s what we do.

   AitchKay

   
   

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   Edited 10/11/2008 7:16 pm ET by AitchKay

1. 
   hvtrimguy | Oct 12, 2008 04:25am | #6

   like this?"it aint the work I mind,
   It's the feeling of falling further behind."Bozini Latinihttp://www.ingrainedwoodworking.com

1. 
   AitchKay | Oct 12, 2008 05:51am | #7

   seeyou and I have posted the same three solutions, and hvtrimguy is right in there, too.seeyou says, “You need two different crown profiles” (my solution #1), “or a wedge on the rake side” (my solution #3), or change the spring angle (my solution #2).seeyou’s ”or change the spring angle”, and my ”Tip the fascia crown out more, and see how it looks,” are basically the same as hvtrimguy’s alternative:hvtrimguy used a square-cut rafter tail, but the crown is cut and installed in exactly the same way that seeyou and I suggest: at 90 degrees to the rake moldings.So, trimmin58, you’ve got three guys on the same page! Who could ask for more?AitchKay

   Edited 10/11/2008 10:51 pm ET by AitchKay

5. 
   mmoogie | Oct 12, 2008 06:20am | #8

   Here's how Asher Benjamin recommended doing it in 1833. I've used this technique. It's pretty simple to do.

   Steve

1. 
   AitchKay | Oct 12, 2008 08:40pm | #10

   "I've used this technique. It's pretty simple to do."Pretty simple to DRAW, at least. But unless it's an historical restoration, it's hard to justify grinding new knives.I look to old vernacular carpentry for worker-friendly designs: plinth blocks, corner blocks for tall base, minimal flush joints, lots of forgiving reveals, etc.Those old designer-builders wanted to make it easy on themselves. So when you see a design that requires going to great lengths to achieve, it usually means the designer was not the builder.I try to KIS(S).AitchKay

2. 
   AitchKay | Oct 12, 2008 08:43pm | #11

   But it IS cool to know how to do that stuff, and I love those old Asher Benjamin books!AitchKay

6. 
   Gene_Davis | Oct 12, 2008 08:51pm | #12

   You either square the fascia to the rafters, or you loft out the crown for the rake, and go get some knives cut.

   It's never been otherwise.

   If I visit a town with fine old homes, gingerbreaded out in 100-year-old trim, it is all the stuff up high that catches my eye. 

   New Hope, Pennsylvania.  Scaneateles, New York.  Cape May, New Jersey.  Evanston, Illinois.  St. Louis has a lot.  Athens, Georgia had more than I could have imagined.

   You walk down the shady sidewalks, looking up, taking care not to stumble, and wonder . . . "why did they go to so much trouble?"

    

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   "A stripe is just as real as a dadgummed flower."

   Gene Davis        1920-1985