I did a little crown job last week with just 4 inside corners. I coped left sides and cut right sides square.
To compensate for the tip of the bottom edge being removed by the cope, I measured length of each board after cutting the miter but before coping. I measured each wall twice with a Bosch laser device accurate to 1/16″; once from left corner and once from right corner, getting identical measurements.
My copes were very clean and under-cut so there was no stand-off where they met the opposing piece.
But every board turned out to be too long by more than 1/8″ and had to be trimmed again to fit.
What do you think might explain this?
Thanks,
Replies
Beats me bruce.
Whenever I measure (with tape) for any trim I take the "mitred" measurement-i.e.- tight from wall to wall. I might add just a bit for a tight spring fit.
I mitre the cut, measure off the long point and then cut to length-then I cope-removing that small pc that butts on the bottom. USUALLY, don't have to go back and shorten.
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Measure from wall to wall using a story rod and rule or if possible just a tape. I do not add or comrensate to the distance. I do not try to spring crown, base and chair rail yes but crown does not spring well for me.
Your problem comes from compensating. After the end is cut and the miter is sharp ,hook the tape (if you are using one) on the mitered end and mark for the next cut.Avoid too much thinking ,just measure and cut,then cope.
mike
I measure the wall like cal (add 1/16" I'm a snapper), then measure the piece like Mike. If all your pieces were exactly 1/8" long, I'd check my tape to the laser...You're not coping one end then hooking your tape to measure, are you?http://www.tvwsolar.com
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"Your problem comes from compensating. After the end is cut and the miter is sharp ,hook the tape (if you are using one) on the mitered end and mark for the next cut.Avoid too much thinking ,just measure and cut,then cope."I said I compensated for the fact that coping removes the tip by measuring before I coped. I did it, in fact, exactly as you described.BruceT
Thanks guys for your comments. Since there was no "of course, that always happens because of ..." answer from any of you, I know it's not a normal situation.I guess I'll have to re-check the accuracy of the laser measuring device and see if hooking the tape over the mitered point of MDF crown squashes the point a little, maybe even consider the meniscus of paint in the corners pushing out the square-cut ends a little.BruceT
I always measue wall-to-wall.
Miter crown and mark length BEFORE coping.
Cope corner.
Cut for length (cut the other side of the mark - cuz I'm a "snapper", too).
I'm pretty sure I'm just repeating something someone else has said here, but it souds like either:
1. A problem between your laser and tape,
2. Measuring after the cope.
No Coffee No Workee!
Thanks for re-starting the thread.I did exactly as you suggest; miter, measure & mark length, cope, then cut off length at the mark.I checked my Bosch laser device against my tape and found it to be dead on.I think part of the problem may be that the laser device is thick enough that it cannot measure exactly into the corner of an inside corner. Any "meniscus" of drywall mud and paint in the corner will make the real measurement somewhat shorter. That corner meniscus would also kick the underlapped piece out a littleAlso, the crown I was using was MDF, so hooking the tape on the point of the miter probably squashed it down a little, resulting in a slightly long piece. Finally, in my caution, I cut length a trifle outside of the line.I'll have to watch all those things next time and see if I can get a better result.BruceT
I find it much easier to measure after the cope is made.
I measure corner to corner. Cut the crown stock to that length, then miter. That way any measuring is done on square stock. The measurement isn't going to change simply because you are planning to miter and cope it, just cut a precise miter.
For square / rectangle rooms I prefer to have 2 butt cut pieces and two double mitered pieces. I also run them long for a spring fit. Vic
I actually had the very same problem when I began using the Bosch laser. Every piece was about 1/8" too long. From then on I always subtracted 1/8" when measuring inside to inside. Never a problem since. I believe the problem lies in the irregular surfaces of the wallboard joint compound.
Thanks. I actually checked the Bosch laser range finder against my Fat Max tape and found them to be dead-on equal.BruceT
I do a little different route. I pull off the vertical step on the top of the cove of the crown. It butts easily for a tape and you can pull off of it on the piece you just cut. Friend of mine showed me that about 8 years ago and I've been doing it ever since. It's very accurate & easy once you get the hang of it.
Do you put up a piece, measure, put up a piece, and measure, etc?How do you measure the piece to be cut?http://www.tvwsolar.com
We'll have a kid
Or maybe we'll rent one
He's got to be straight
We don't want a bent one
He'll drink his baby brew
From a big brass cup
Someday he may be president
If things loosen up
"Do you put up a piece, measure, put up a piece, and measure, etc?"Yes. It's easy though because I use one of those Leica laser tools. I also cut left & right coped pieces, leave some play in the ends and after I hold it up to the correct position, nail it home. It's good to have a line to follow though especially if your walls & ceiling are fukaksid.My laser's better than Sheps, but don't say anything.
I've used a Leica, t'was nice.http://www.tvwsolar.com
We'll have a kid
Or maybe we'll rent one
He's got to be straight
We don't want a bent one
He'll drink his baby brew
From a big brass cup
Someday he may be president
If things loosen up
"I pull off the vertical step on the top of the cove of the crown."I don't understand quite what you are saying. The profile I was using had 160° convex curves at top and bottom, but I know most crowns do have steps, so I'd like to understand what you're doing.BruceT
On the top of the cove at the bottom of most crowns is a little vertical step that's usually around 1/8" to 1/4" thick. It works surprisingly well as a measurement point reference. you can butt it or pull off it depending.