Cutting crown

[Scott Baer]

I have a rather big crown moulding job that I am tackling. All horizontal ceilings, but lots of funky wall angles, so I bought a Bosch digital miter finder thinking that it would make my job a lot easier. However I think I am missing something.

I cut my crown in position using a miter box I made attached to my Dwalt DW715 12" miter saw. I spent the time to make the box quite accurate to make my job as easy and nice as possible. The angle finder I bought is accurate to .1 degrees and has 17" legs to span the dip in the wall from the cornernbead buildup.

Hears the deal.. I thought it would be a as simple as measuring the angle using the miter finder, dividing that in half, and using that for the angle of the miter saw setting. However, it doesn't appear to work. Sometimes I am a degree or two off. Do I need to use 180 - the measured angle? Maybe apply that to only inside corners, or maybe just outside corners? What am I missing? *Or am I not missing anything and am just too sloppy? I am trying to be very meticulous.

[Ben Franz]

A few things to consider:

1. Cutting crown in the "sprung" position is very sensitive to getting the spring angle exactly right - even a fraction of a degree error can cost you some hair DAMHIKT.

2. The angle finder will give you an exact angle only if the two legs are sitting flat on the adjacent walls. Nearly every corner in the real world is imperfect and the small deviations at the corner can cost you some more hair (notice a theme here?).

3. Coping inside corners is the accepted method for dealing with these problems - it takes some time to learn but it's the best method, esp. for stain grade work. For outside corners, I make test pieces from scrap crown and use a trial and error to find the exact angle.

4. Marking the wall and ceiling with lines at the correct distance to maintain the spring angle helps - it's easy to get the crown a little bit off angle when installing and, well, you know....

5. If you have a SCMS and a trig calculator, there are general formulas that allow you to compute the bevel and miter settings for any crown geometry (spring angle) and any inside or outside angle. Then, the moulding can be cut flat on the SCMS. I've had pretty good results this way installing 8-10" stain grade crown. It is a little tedious, though. If you want to try it, Fine Homebuilding published the formulas back in the late 80's - I have the article somewhere and I can send it to you - PM me if you want it.

Good luck.

[Scott Baer]

Thank you for the reply.

With the box I make and my meticulous attention to detail, I believe all cuts are near perfect.

I am not a good Coper. Besides, painter said just to miter cuz it's gonna be painted, not stained.

The miter finder I have will give me the miter and bevel if I want it. However, I haven't found that to be as accurate as cutting in place.

Can u confirm that, theoretically. All I need to do is take half of me angle finder reading regardless of it being an inside or outside reading?

[Karl Brogger]

I am not a good Coper.

You think you're going to get better at it through magic? Only way to get better at something is to do it. Besides coping is way easier than mitering.

If its bigger stuff use a jigsaw with a very small blade, and a beltsander, finish it off with a rasp.

Rolling the crown will alot of times pull things enough to get the top and bottom of the joint looking good.

[bill mullin]

For inside corners, subtract a half degree on each cut; for outside corners, add a half degree. Kind of a pain, because of the stops on the saw, but it works.

[Scott Baer]

Thanx again guys. Your hints are helpful. I still don't have it straight in my mind, thought. Very simply, let's say, on an outside corner, if cutting the crown in place upside down and backwards, I'd I measure the outside corner as 88 degrees. Is my saw setting supposed to be 44 or 46 degrees? If I were to cut a flat piece of cove or something, it is clear... 44 degrees. But it seems as if since the crown is oriented on the saw differently, I might be supposed to take 180 - 88 degrees, then divide by two.

[bill mullin]

Thanx again guys. Your hints are helpful. I still don't have it straight in my mind, thought. Very simply, let's say, on an outside corner, if cutting the crown in place upside down and backwards, I'd I measure the outside corner as 88 degrees. Is my saw setting supposed to be 44 or 46 degrees? If I were to cut a flat piece of cove or something, it is clear... 44 degrees. But it seems as if since the crown is oriented on the saw differently, I might be supposed to take 180 - 88 degrees, then divide by two.

I've never used one of those before, but I'll bet in your example you would subtract the angle from 180, then divide by 2.
In a situation where you would cut 2, 22.5 angles (outside miters), I'll bet your device would measure 135 degrees. So 180-135 is 45, divide by 2.

I've never seen any outside angle be a true 45, 22.5, 30, etc. The corner bead always throws it off.

[Scott Baer]

Ahh, yes, my tool would measure 135. I spose that would be the case on inside corners as well?

[Andrew Minear]

Ahh, yes, my tool would measure 135. I spose that would be the case on inside corners as well?

Say you have an outside corner to crown. That should be two 45° cuts. If The left leg is square at 45° and the right leg veers away at 47°, then an angle finder wouldn't give you a true reading. It would split the angle so both sides are wrong.

I carry cheap paint grade crown to the jobs to make test cuts, and find the exact angles from those. HTH

Andrew

[Rich Engelhardt]

Starrett 505A-7 7" Prosite Protractor.

Mindless.

Fit it to the inside or outside corner, read the dial and use the digital protractor to set the miter saw to the right half degree if need be.

Bit pricey @ $50, but, I have 5 houses to take care of so it's worth every penny to me.