Crown Molding - Going Bananas!

[sharper]

Hi - I am installing crown for the first time - and am having a bit of confusion figuring my miter angle - I am going with the butt - coping method and here are my figures:

inside corner = 90 degrees
spring angle = 35 degrees

what would my miter angle be for the coped end of my mold?

Thanks so much for your time!

Sherry

 

[inspectorD]

It depends on what the walls look like too.

You need to cut an experiment piece. This is the only way to get it perfect in each corner. Put the crown on the saw the way it will be installed and set one cut at 45 degrees.
Usually the crown has to be upside down when you cut it.
This will give you all the angles you need if you are using a compound miter saw.

We have many more answers to crown in the carpentry and woodworking forums, check those out.

 

[TaskBoy]

I'm far from being an expert at crown but I did figure it out and my job came out very nice. So...

You're talking 90 degree INSIDE CORNERS, right? As far as I understand, the spring angle wouldn't have any bearing on it ("spring angle" being the angle of the mould's face if installed, right?). I never even bothered with it doing butt/cope. Even if your "90 degree" inside corners are off a tad, butt/cope covers that up. I start with a piece of moulding that is a little longer than the span to cover. I just cut my miters (always upside down on the saw) at 45 degrees (by swinging the saw blade, not tilting it). Make sure your mould is firmly sitting at 90 degrees on the table and fence (again, upside down). This is an INSIDE MITER cut for INSIDE CORNERS. Once cut, you then take a coping saw, an electric sander and/or a half-round file and steeply back-cut or clearance the area from the edge of the curves of the crown's design back into the mat'l behind it. This reveals the profile of the crown's design and makes a knife edge that will butt up to the adjacent piece. The latter piece is cut 90 degrees and butted up to one side of the inside corner first. The miter cut piece I described is then attached to it. Once I've made the mitered end, I then mark how long I need to cut it off and only do so then--gradually cut to get a snug fit. Crown is confusing at first and I hope this helps and didn't confuse you. Here's a couple links with some pics that really helped me.

http://www.crownmoldingshop.com/cutting.htm
(nice aerial drwg. of butts and miters)

http://www.rd.com/17891/article17891.html
(good pics of the profile back cutting)

http://www.extremehowto.com/xh/article.asp?article_id=60354

​

(small but good pics of the saw settings and look of the diff miters)

 

[inspectorD]

Spring angle only matters when you cut your crown flat on the saw bed. This would make you need changes in the degrees on your compound angle miter saws.
It is the only way a professional will cut crown. We are usually doing miles of this stuff.
For DiY folks, the upside down at a 45 angle is fine. I also trace the outside cut with a pencil if you are going to cope it in. It is easier to see the line and use the coping saw.
Some crowns can only be installed with miters, this is because the crown is so intricate it is impossible to cope without it looking bad.
If you are using a basic mill crown like Brosco, you should be fine.

Good luck, practice makes it easier.

 

[TaskBoy]

Thanks for the clarification about spring angles!

 

[mikemeier]

If it's MDF and you're looking for an easy out (paint and caulking) I would just do a miter cut. It's not as perfect though.