Cutting crown molding angles

[Sawdustd]

I'm about to add crown molding to 2 bedrooms in my daughter's house and discovered the walls are not at 90 degrees (inside angles). Some are more and some are less. One room has a fireplace which juts out 8" and the "outside" corners are not 90 degrees. Question is: which angle(s) on my compound mitre saw do I adjust -- the bevel angle, the mitre angle or both? I'll be using crown molding with a 52/38 degree wall angle. I think that's called the spring angle.

My saw has a pre-set 31.6 miter angle and a mark on the head for 33.9 bevel angle.

This is rocket science. Help please.

Dave

[Joel H.]

Here is a URL for DeWalt. It has nearly all the information you'll need. Page down a couple of time to see the cutting angles for different wall angles.

DeWalt Crown Molding Chart

HTH

Joel

[Sawdustd]

Joe - Just what I needed. That indeed is rocket science made simple. Thanks so much. Saved my bacon.

Dave

[jteneyck]

I always use the vertically nested method so that you only have to adjust the miter angle. No rocket science required. Measure the angle. Divide by two and that's the angle you set your miter at. The only thing you have to keep straight is to put the molding against the fence upside down and set the miter for the right direction. I put a pencil line on the molding to make sure I don't screw it up because, well, because I have.

John

[Steve N]

I had an old Bosch 10 slider for a lot of years before I gave it to my BIL. It had this picture attached to the base. I've given it to a lot of people, that way wherever the saw is, the diagram for crown is with you too. Copy, have laminated, and have at it.

[mike4244]

Those angle detents are for cutting crown on the flat. If your saw permits you will find it easier to use crown stops and cut vertical.
For outside corners use a bevel square to find the angle. Whatever the angle comes out add 1/2° to each cut side.Example, if the wall shows
88°, set the base to 44-1/2°. The crown is held upside down and backwards on the saw base. Crown stops help hold this angle consistent.The ogee is normally at the top, the cove at the bottom.
When cut crown turn it upside down. The backwards part is referring to what end to cut.Swing the saw to the RIGHT and lock in at 44-1/2°.You will be cutting the right end of the crown
Make the cut.Turn it right side up and you have the LEFT outside miter.On the mating piece you cut the opposite way,swing saw to the LEFT,cut the left end and now you have the Right outside miter.
The addition of 1/2° to each side makes the miter tight,you can use the same method for door,window trim ,base etc.The gap at the back is not noticeable,the front of the miter is tight.
Coping the inside corners is preferred.Set up the crown the same as for the outside miter.Don't be concerned about the angle unless the angle is not intended to be a 90°, like 120° on some corner cabinets.
Lock the detent on the 45° for ordinary inside corners,even if the are not exact.Remember that all the cuts are done with the crown upside down.
Swing saw to the RIGHT,cut the Right end of the crown,this gives you a mitered corner that you can cope.Swing saw to the LEFT,cut the LEFT end of crown and you have the opposite inside miter.
Practice on scrap at first.
I cope with a saber saw using a 14 tpi blade. I leave the base square to the saws base. The saw base sits flat on the mitered cut.I make relief cuts first,especially at the ogee.The flat steps at the ogee and the cove must be very thin.Most of the time if a cope looks good but needs to go a bit higher to be perfect ,the cause is the flat areas are too high.I finish with a variety of shop made sanding sticks.80 grit sandpaper works well.Attach sandpaper to a dowel,paint stick etc.
Works better than a rasp or file for me.
mike

[FS7]

Sawdustd said:

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I'm about to add crown molding to 2 bedrooms in my daughter's house and discovered the walls are not at 90 degrees (inside angles). Some are more and some are less. One room has a fireplace which juts out 8" and the "outside" corners are not 90 degrees. Question is: which angle(s) on my compound mitre saw do I adjust -- the bevel angle, the mitre angle or both? I'll be using crown molding with a 52/38 degree wall angle. I think that's called the spring angle.

My saw has a pre-set 31.6 miter angle and a mark on the head for 33.9 bevel angle.

This is rocket science. Help please.

Dave

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Assuming the walls aren't terribly out of square (and the crown will be painted), this is pretty much what caulk was invented for.

[rfd8w5]

Cut it upside down and cope your inside corners. Coping hides those discrepancies. I've been a trim carpenter for thirty years and the only time I have had any trouble with an inside corner not looking right is when I mitered it. Outside corners are a different beast of course. Starrett makes an excellent miter protractor that gives you the correct miter angles. Unless your crown is really huge cutting with the bottom edge up and the crown sitting on the saw table in the same orientation as it will on the wall will give you excellent results. Crown "dogs" which will position the crown on the saw the same way every cut are a great investment. However, pieces of masking tape on the saw with pencil marks will also work to position the molding.

[rfd8w5]

Putty and paint make a carpenter what he ain't!!

[Sawdustd]

Thanks Rich and ALL for the information and advice. We/, my son-in-law and I got it done. Far from perfect but close enough. Drywall compound was the saving grace. The wall corners weren't square and some walls and ceilings were bowed. Three more bedrooms rooms to go when I return in early summer.

Its truly "This Ole House" built in 1865ish in Corning, NY by one of the 3 original owners of Corning Glass. It was a Mansion, 4K sqft. and the workmanship/ craftmanship was superb in every detail. In the late 1970's the original family family sold it and the new owner divided it up into 6 apartments an then let everything go hell, inside and out side. Criminal is mild word. My daughter bought it "as is" for $95K and are is now living there. The house is structurally sound but needs a TON of work not to mention a TON of money to restore. All in 10 or 12 yrs as John Wayne would say! The original interior trim and molding is beyond beautiful. Rich, you would have a field day with this house. Unfortunatly, my SIL is not a woodworker but is a good helper and we work well together. Next time I go up, I'll take pictures.

Dave