Crown Molding/Cornice angle cutting questions???

[Harold Burrell]

I am trying to build a cornice for a hutch like the one below. I am milling all of my own stock, including the crown molding (which will be a simple cove done on my table saw).

Anyway...my questions...

First, you will notice that the plans call for 40°. How can I make that happen when my table saw will only tilt to 45°? Then...how do I make it so that the angle at the top of the molding is right (I'm guessing 50°???)?!

ANY help would be appreciated.

Man...I wish I had studied harder in geometry class... :(

199932

[Harold Burrell]

Would I be better off just going with 45°? Would it make that much difference looks wise?

[Neil Brooks]

Do you have access to a compound miter saw ?

[EDIT: Ah. Sorry. Just noticed: You have to make that cut across the long dimension. CMS ain't gonna' do that. I've gotta' think on this one. My first thought is "jig," but ... how to make it. I wonder about the tilt table on a bandsaw ....]

[Mike Henderson]

When I have to cut an angle that's more than 45 degrees, I always look at cutting the complement. So in this case, (if I understand your situation) if you lay the board down flat on your table saw you'll have to cut a 50 degree angle. But if you stand it upright (on edge), you can cut a 40 degree angle. The question is how to hold the wood while you make that cut. I would attach the board to another board with the board you want to cut upright. If you use screws, make sure you don't cut through one.

Maybe someone else will have some good suggestions.

Mike

[Joe Fabbri]

Hi,

Am I missing something or is there a mistake in the diagram? Those two angles shouldn't both be 40, they should be 40 and 50 like you're saying. Anyway, standard spring angles (the angle the crown molding springs off of the wall, or in this case cornice fascia), are usually 38 (bottom) and 52 (top), or both 45. If you want more of a projected profile--more dramatic looking perhaps, then simply go with 45 for both. If you want it more subtle, then go with 38/52 or 40/50. Now, if you don't do 45 for both, then I think you should be able to stand the board upright (on its edge) and run it through the table saw. This way you can get the lower angle.


I see someone's already posted this suggestion. Anyway, if you don't see how it works exactly, draw the profile (with the spring angle you want) on the end of the board, and stand it upright with the blade tilted and match up to the line you've drawn.

Joe

[Peter Quinn]

I use a tall Fence that slips over the primary fence for things like crowns. You cut your angles BEFORE running the profile, it's much easier. It takes four passes, two laying down, two standing uP on the tall fence, to cut the spring angles and the plumb cuts. A jointer can be used to clean up the show edges. You can also attach a tapered shim to your fence to go Past 45, make sure you are holding the work securely if you do that.

[Harold Burrell]

Thanks all.

I went ahead with the all 45° approach. It just seemed a tad safer than running the board vertical on the TS (especially since I had already cut the cove).

Now for my first attempt at cutting molding miters.

(Oh...my aching brain...)

[Joe Fabbri]

Harold, if you have a compound miter saw, then you probably got a chart of common spring angles with it. This should tell you what bevel and miter angle to set the saw at. Here's a link to a set of angles: http://www.sarasotacarpenter.com/crown.htm

I'm learning this stuff at the moment too, so you've posted this at a good time.

Joe

[Harold Burrell]

I'm supposed to set the miter to 35.26°??? How in the world is that possible?

[Joe Fabbri]

Beats me! Haha. It has to do with geometry. Maybe someone on here more experienced with crown work can chime in with an explanation.

[Neil Brooks]

Some of the compound miter saws have "preset detents" at some of the commonly used, but odd-numbered angles.

[Joe Fabbri]

Oh, I read the question as, how could that be the case. If the question is how you would actually set the saw at such an angle, like Neil said, the saw (compound and regular miter setting) should have preset stops, where the saw will click and lock itself at that angle. So, when you get to 22.5 or so degrees, for instance, you will see the saw click and stop, along with 30 or so degrees, or whatever it is. So, they are made to stop for common crown spring angles.

Joe

[Chip Lindley]

I have never cut a compound angle on a RAS or chop saw in my life! It is just too easy to cut some triangle blocks exactly of the angle that the crown moulding would be attached to the wall or casework. Attach the angular blocks to the back of the crown with wood glue and air brads. Position the back of the moulding against the saw fence and chop a 45 degree miter on the end with the blade exactly vertical at 90 degrees.

If wall corners or casework are an exact 90 degrees, all is well. IF the angle is more or less than 90 deg., use an adjustable try square to transfer the exact angle to a protractor. Divide in half to find the exact miter angle needed for that odd corner.

Unsquare corner angles in room interiors are the rule rather than exception! Those are time-consuming enough without all the headscratching that compound angles entail. Some finish carpenters rely on wood putty to make everything right. But, I demand a hairline joint at my stain-finished moulding corners. Call me particular.

~~Chip~~