Compound angle crown moulding miter

I'm pretty good at trim work, mitering, coping joints, and crown moulding. However, I have no idea how to execute a dual-angle miter with crown moulding. The situation is that I want to put sprung bed moulding around the perimeter of a vaulted ceiling. That means that on the inside corners (at the center beam and at the bottom of each side of the ceiling) I need to make a 90* angle PLUS a ~15* angle to account for the slope of each half of the ceiling. How?

After reading your post again, I think you have a boxed beam at the peak and your trying to turn the crown along the beam as well, you'll need another crown block there as well.

Joel,
You sure like a challenge. First the big problem is the same width moulding can't be used on the side walls and the end walls (gable ends) due to the angle of the vaulted ceiling. The end wall width of the crown increases as the angle of the vault increases. The side wall width of the crown will not increase the same as it is leaned back to match the angle of the vault. You'll need to lay out (or CAD) the corner intesection to get the two widths and then mill the two different cross sections.

Is the crown you're thinking of a shaped moulding or just flat! Ether way, the compound angle needed will be a true nighmare. Lots of computing angles and trial and error. I have a hard time with it even with the "dead stops" on my compound miter saw!!!

If I were you, I'd give up the crown idea and just go with a 1x2 cap flat against the wall at the ceiling intersections. That's how they do it anyway. You'll still need to have two different widths so they match in the corners.

Is this to finish off your dinning room?

Crown blocks?? They are for people who can't miter!!! Someones been spending too much time at Menards or HD!!

65 'cuda wrote: Pete, I'm a trim carpenter, I've learned a long time ago to answer the question that was asked, I could have gone into the reasons the profiles were not going to match up but it seemed silly. If he wants to have three different crown profiles milled for one room I guess it could be done that way. Should have kept my mouth shut.

Gary,
In my reading Joel's question I got the impression he did ask and the reason I went into the different profile answer.

M3Fan wrote: I have no idea how to execute a dual-angle miter with crown moulding. The situation is that I want to put sprung bed moulding around the perimeter of a vaulted ceiling.

Please understand that my comment about the crown blocks wasn't meant to offend and in the situation Joel is in may be his only choice if he doesn't want different profiles milled. (That would be even a tough challenge for a custom millwork shop!! Plus, very expensive!!)

BTW, I did a crown job where I coped the corners. Wow, what a PITA!! But, it did come out very nice!! Another one I did in my in my dining room (painted) was done with finger jointed stock. Looked at it the other day only to find one of the finger joints opened up. Typical of the wet wood we get these days even with moldings!

To be a little more technical, I just looked at a trig table.

The secant of a 15 degree angle is 1.0353. Thus the difference in height between the 15 degree vaults, and the regular section of the wall will be 3.53%. On 4" crown thats .1412 inches, or just over an 8th of an inch. Cheating the the vaults up about 1/16th of an inch, and the regular sections down about 1/16 of an inch gets you there.

4" crown will be less than four inches when installed because of the angle to the wall. Thus the actual gap will be something a bit less than .1412 inches.

Again, not such a good option of doing the crown in natural wood.

BKH

OK gang. Wow. I knew this was the right crowd to ask. I'm starting to think the crown (as compared to a 2X2 or something) might not be a good idea, although the moulding has been purchased already, and poly'd. Couple answers:

1. Yes, bed molding is somewhat complex cross-sectionwise. For the music people out there, the profile looks like a quarter rest.

2. No, it wouldn't be painted- just poly'd (done already)

3. Never thought about different widths- that for sure isn't happening since we're talking about Menards stock here. Like Brian said, maybe I can cheat on it a bit.

4. The gap between the beam facade at the peak and the planking MIGHT be too big for a 1X2. Of course, I built it thinking the molding would be there. I needed the gap for the T & G to engage.

My neighbor is a carpenter by trade, for fine cabinetry and trim work,and even he is a little baffled by it- although he's the one who suggested it. He mentioned making some helper piece that is mitered one way on one side and the other way on the other side, etc. He said he'd play with it and get back to me- that was weeks ago. I like the 1x2 plank idea- maybe a 2X2 will do it. I'm still a little confused as to how to miter even a 2X2 like that. Brian, awesome calcs there. Way out of my league.

Joel,
If you do go with the 1x2 idea, I've got a couple of suggestions.

Chamfer the top edge where it bumps the T&G. Then any minor gaps will not be noticable. The T&G is never dead flat and straight on the ceiling. This is from personal experience. The chamfer on the T&G joints is for the same reason because there's aways some that never really fit together nicely.

You're inside corners should always be coped. In the case where you're using square stock 1x4 for ether a base or a 1x2 cap, this results in a easy square cut plus of course the angle cut for the slope of the ceiling.

If you ever run into the problem of getting the last piece of T&G in up agaist a surface, it's common to rip the backside of the groove off and then face nail the last piece in place.

Now if we can keep HW out of this thread changing the tongue "and" groove comments to tongue "in" grooves, we'll be doing ok!!

After reading up on this a bit, I might take the challenge and use the bed moulding. There is definitely some good stuff out there on the topic.

Brian and Pete..you guys continue to amaze me. I like reading your posts even when I don't have a clue what you are saying.

BTW..not to be nosy Brian but...you got "appointments" to go on? Some kind of job change here? Did I miss something?

john

+1 on the saw Joel, I got me a yellow one but basically did the knee thing on the floor for years. Never a bad investment to buy tools. Wait til you buy a welder, the fun never ends!

Now for a comment from the peanut gallery...Do your best and caulk the rest.
bj