Installing crown moulding

Calculations and tools for cutting crown angles. May 17, 2003

Any tips on installing/cutting crown molding? Right now it seems to be a huge bottleneck in my installs, especially coping inside corners.

Forum Responses
(Cabinet and Millwork Installation Forum)
Here's one take from a maker/installer's point of view. If you are installing crown into a wall to ceiling situation with bumps, out of squareness, etc., then coping is very useful when coming into an inside corner. My approach when setting crown to my own blocking set on top of the cases (I build frameless) is to cut all miters in the shop and deal with only square cuts at the site. I try and deal with anything possible in the shop because it always seems to get more difficult once you are on site. I like a glued miter joint when I'm dealing with a flat and square background of my own making. Not sure if this addresses your problem areas but thought it worth a try.

From contributor P:
One of the most difficult things for a millwork installer to deal with. All shops have to figure in an extra 4 or 5 bucks per inside joint on the estimate. No magic drugs solve this bottleneck.

I use a crown molding software program to calculate the bevel and miter cuts. So no trial and error in the field. And I put up the long pieces first with straight cuts so the shorter pieces have the cope. I use a tablesaw on an installer's workbench (foldup unit) to hog out most of the material for the cope. I use a sanding block or belt sander to finish. The bigger the crown, the harder it is to do. I tried the coping foot with a jig saw, but it seemed to solve one problem and create another.

Crown over 4" is really difficult, no getting around it. Small bandsaw, jigsaw, coping saw, they all have their drawbacks. Even the best craftsman will work hard to make a good crown install. Charge your customer for it.

The best improvement I had with installing crown was the software. I use a program by "Easy shop series" but I don't see it marketed anymore. There are some other programs. Also find a miter chart and give everyone a copy. Not quite as good as software, but you can get fairly close.

View a sample of Gary Katz's Crown Installation Video

Gary M. Katz

From contributor W:

I have been considering two alternative answers to coping mouldings, and wonder what installers acceptance would be to:

a) Getting all mouldings supplied with pre-machined cope on both ends or
b) a small template guided machine that will machine the cope on site.

Would either of these ideas be of interest to installers?

From contributor P:
On small jobs I plan out pieces and cope all but the last piece. If crown is long enough to do a room in 4 pieces, I cope 1 end on 3 pieces in the shop and the last one is a cut to fit double cope in the field. Professional installers still need to be good at crown install - it's their job to learn it.

I've never seen or heard about any kind of template or machine to cut a cope. If you know of one, share with the world its existence.

A real good math freeware program will calculate compound miters. You just need to be a little math savvy.

From contributor W:
Contributor P, I have figured out the design of such a machine. I don't think one exists already. I am trying to decide if it should be built heavy-duty for the moulding manufacturer to use, or lighter and portable for the carpenter to use on-site.

From contributor T:
I always install the shorter pieces of crown first. I cut the longer pieces 1/8 -1/4 inch longer to get a good crush fit on the copes. I always use a coping saw on the coped ends.

From contributor P:
I suppose if I were to design a coping machine it would be the size of a jigsaw and operate like a band saw. It would use a spiral-rasp type of blade. This thing would be able to cut and grind at any angle and have a small enough blade to get into little corners. And to have a router type collar that rides on a custom made template would speed things up a lot. But you would have to have a 3D sort of template to work well. Triangular, increasing depth kind of thing.

Maybe a good business for someone that has a metal CNC machine. Just fax in a drawing of your crown molding and a week or so later get your template. Kind of like how my custom shaper knives get done.

I don't know if Art Betterly is still around, but I remember seeing him about 20 years ago working with Porter cable on designing odd router applications.

From contributor W:
Customers I spoke with last week said that the coping machine should be portable and inexpensive for use on site. They thought that shipping pre-coped mouldings would be too easy to damage in transit.

My machine would use a small router bit or rasp blade, working from the same 1:1 plastic template Weinig uses in our grinders (cheap to duplicate, can be readily supplied with moulding). All I have to do now is make it!

What determines if cope should be cut onto LH or RH piece of moulding? How important is that choice? A machine gets more expensive if it must do both.

From contributor T:
It depends on which way ( right or left) you go around the room when starting. The last piece is usually double coped ( both ends). It usually doesn't make much difference to me which way I go around the room.

From contributor W:
I had not considered double copes, but now I will - glad I asked.

I just hog out the waste to within a sixteenth of the finished line with a jig saw held with its base plate a bit above the clamped work piece. Then I finish up with a Foredom rotary tool with variable-speed foot control. Total time per cut= maybe 2-3 minutes?

As a part time cabinet/furniture maker, I do get roped into crown installs on occasion. Since most of my crown are custom profiles, many of which are large, full coves which extend to full horizontal at the ceiling. These cannot be coped due to the razor thin piece that remains. Thus mitering is the only way. I plan for the time and charge for it.

As far as pre-coped, here is my bit for the small shop/installer. I did a crown job for an enormous library coffered ceiling. The openings were between two and four feet square. Some were trapezoidal, thus adding to the grief. Several hundred cuts. Now the fun part. It had to be pre-finished cherry with conversion varnish. The original shop/installer failed to install the crown and left the state. Home library was occupied. With no cap on price, I pondered it for some time, knowing good measurements and pre-copes were the only hope.

Since my shop work revolves around my SCM T50 shaper, I had a coping profile cutter made. I ran all the crown, then cut the lengths to exact for butt. I then made several fixtures to hold the crown at the required angles, right and left. These were also designed to eliminate tearout. The ends of the fixture were cast out of Bondo to give a perfect fit to the crown. This was the trick for a smooth cut.

In a nutshell, my shaper was turned into a coping machine. It worked great. All pieces were fit, filed if required, identified, brought back and finished. All were then pin nailed upon installation. In the end I had an amazing respect for the installers coping and fitting on site. They earn every penny.

Contributor W, if you have a machine that copes to a template, would you still be able to mount the crown at various angles to the wall? When installing crown in a room with a cathedral ceiling, one piece may be tilted 10 or 15 degrees toward the wall to keep things lined up.

Another thought is a machine that uses a sample of the crown itself as a template. This would make it useful to guys that don't make their own mouldings and wouldn't have templates from their knives (that they don't have). I make mouldings but use a coping saw to cope them!

From contributor J:
I've installed a fair amount of crown for friends and relatives on a freebie basis. Now I have several paying clients who want crown installed and I'd like some suggestions on how to price my work.

From contributor P:
Contributor J, several ways to look at it. About 3 bucks per foot, in an average situation. Plus add about 5 bucks per joint when the frequency of the joints exceeds 1 per 12 feet.

Another way is to figure what you are going to pay yourself per hour. For me, it's 35 per hour. And I figure about 10 to 12 feet of crown installed per hour. So a square room, 12 x 12 is a half day's work to set up, fasten blocking, install, putty holes and move on to the next room.

If there is high ceiling and you need scaffold, or furniture is in the way, add the costs to the per foot method.

And to speed things up, figure out what the angle of the crown is to the wall, and do some of the cope joints before packing to the job site. The compound angle formula from my spreadsheet will figure the angles in a jiff.

Enter this in your favorite spreadsheet.

compound miter formula - entered in row 15

cell 1 - slope a in degrees

cell 2 - A15*PI()/180

cell 3 - slope b in degrees (note: slopes a and b will be the same when figuring crown molding)

cell 4 - C15*PI()/180

cell 5 - wall angle in degrees

cell 6 - E15*PI()/180

cell 7 - ATAN((COS(B15)*TAN(D15)+SIN(B15)*COS(F15))/SIN(F15))

cell 8 - G15*180/(PI()) miter cut in degrees

cell 9 - ATAN((COS(D15)*TAN(B15)+SIN(D15)*COS(G15)/SIN(G15)))

cell 10- 90-(I15*180/(PI())) bevel cut in degrees

Why can't you either notch the butt end or drill a hole that will allow the wires to pass through? Just a thought.

From contributor T:
Cut your crown in a miter box. Turn it upside down to cut your 45 degree cut on the ends. Roll the crown in the miter box so the wall and ceiling surfaces fit to the back fence and base of the box. Swing the saw to the left to 45 degrees to cut the left end and right to cut the right. Remember to watch for your fingers.

I once coped 8" solid cherry pre-finished crown on a table saw. It worked perfectly. It didn't show light when a lamp was held behind the joint (it was flying crown, for a light bar above it).

When I install crown I use a half miter joint (that is a piece cut square and then miter just the bottom portion to about the main curve) then I fully miter the other and cope out the top half with slight undercut leaving the mitered portion on the bottom). Installed looks like mitered on both and you can cut full for a frog hair tight joint. Works equally well on any moulding-base/chair rail/crown/wood top edges. With 2 men we can install really fast and as I said very tight joints (will almost install itself as it self-aligns the joint). I've got an old hat working with me and he swore he could install faster by just mitering both pieces - result=less than adequate/takes a few more seconds to half cope, since only coping half the mould width - and usually the less ornate part - but installation goes much faster. He got on my page after a short demo. Try it. You'll like it. Faster and better.

Contributor W, the gizmo you're considering. Are you sure it would work on sprung crown?

From contributor W:
That depends on what a 'sprung crown' is. Does this mean a crown that is adjusted for a different wall angle - as an angled attic wall?

Sprung crown would be applied at a 45-degree angle to the wall (as opposed to “solid crown” which is applied flat, like a base or chair rail).

From contributor W:
I think it will work fine with sprung crown, at any wall angle.

For the record I don't plan to develop my own cope machine until I see the system already developed by Bill Shaw (the trim cope machine is called the Copemaster, Shaw Millwork, CT). I need to be sure that my concept does not conflict with his.

I am installing crown moulding (#LCM96?) over some kitchen cabinets. I have a corner wall unit with 2 inside 45 degree angles to the other cabinets, and am getting my butt kicked trying to cut the moulding properly. I'm not sure how to position the piece on the miter saw to make the cut. Any suggestions?

Lay your crown on the miter box up-side down (cove up against the fence). Now any measurements you take from your cabs will be on top of the piece on the miter box. Set up some crown stops or something set to hold the crown from slipping down. This way when you make multiple cuts, they will be the same.

The comments below were added after this Forum discussion was archived as a Knowledge Base article (add your comment).

Comment from contributor A:
First get a Bosch DWM 40L electronic miter gauge and use it for all corner measurements as it figures compound cuts/miters on crown based on the spring angle. Only drawback is that spring-angle has to be inputed for each measurement.

For crown under 5" a regular miter saw with 3" tall fence has been modifed by drilling holes through it to allow a strip of wood (2x) ripped to spring angle to be attached to fence at a height that allows for wall surface of crown to rest against fence. Then set
angles by cutting a left and right miter angle, and you're left with exact index where the blade meets crown, enabling incredibly fast and accurate cuts.

For crown larger than 5" we use an old saw-buck with an auxillary wood (3/4" ply) cutting surface (to index kerf). I measure all sides at once, cut and install the shortest side first (cut to exact length) then spring the longer pieces in place (depending on surface - drywall or wood - cut 1/32 to 1/16 longer).

Haven't coped a joint in years.

From contributor B:
I have been a carpenter for more than 25 years. I have installed miles of crown molding (more than tens of thousands of feet). I have had many a mechanic frown and shake his head at me with a look of disapproving malice. I miter inside corners. If I can fit it, I put a brisket or two in the joint. I always take the time to jig up the chop saw to hold the stock (broom handles in the holes of a 15" Hitachi with a rip of plywood on the back fence and across the front will handle crown up to about 8"). Building a reverse fence and bending back some of the blade shroud will take you to a little better than 9". When it gets bigger than that and I have to resort to a compound miter saw, then I use at least two saws and a jigged chop saw with smaller stock to set the angles on the compound saw. I will admit that I "dance" a little with the reveals, and at times, I only tack the build-up parts to open up the dance floor and find a compromise.

Carpentry is a controlled series of screw-ups. If floors and ceilings where perfect (and stable) there would be no need for molding. My priority is tight lasting joints. I feel I can achieve that faster with miters. I get the angle right with flat stock, cut the crown from the bottom dimension and tap with a wood block and hammer until airtight. I do cope simple trims like Ogee and quarter round, primarily because it saves the effort of finding the angles (it seems that most inside corners in drywall construction are less than square). Strangely, it does not matter to me whether the teeth of the coping saw face up or down.

Here is another can of worms. When it comes to splices in the field, I butt cut the joints. I can see the heads moving left to right in disapproval. Long lengths of crown molding are sprung into place and under an ever-changing amount of pressure. I have seen even 22.5 degree scarfs walk out of flush after five years. Sometimes simple is better.

Comment from contributor C:
I'm with Mr. A. I cut my first cut at exactly 45 degrees and at a 45 degree angle, upside down. Then I check the fit with a scrap piece and gauge a slight tip, either positive or negative for the next piece to eliminate the gap. After a few tries you'll get it by eye. Result... no plugging in numbers and calculating, and no coping. Most rooms are close enough to 90 degree corners for this to work. Works on 90 degree inside or outside corners.

Comment from contributor D:
I just finished installing crown in four rooms in a 20's English Tudor home with very uneven walls. Initially I used the Collins Coping Foot mounted on my jigsaw which was working okay, but I had various imperfections and it bothered me. Plus, holding a jigsaw upside down is unnerving for me. I think it's dangerous, and when I get off line, I can't easily back up and cut in another line because I'm in a cut line.

After giving a lot of thought to what tool would be able to eliminate the backside of a mitered corner to produce the perfect cope, it dawned on me that a Dremel with the right bit might work. After trying all my bits, I was surprised at how affective a drum sander bit was. Because of its large round drum side, I was able to shape and grind away the material and follow the profile of the crown with a lot of control. In areas where the profile came to a point, the drum sander was also effective by turning the head of the bit sideways and cutting in with the top edge. Excited by the idea, I researched a more sturdy bit and found that Dremel makes a carbine sanding belt which I found online for $6 each. I just finished the job and my coped corners are virtually flawless. The carbide sanding belt with Dremel allowed me to shape away the perfect profile and create great fitting coped corners. Using the dremel tool I have to remove all the "white meat" of the cope by grinding it away, but with the carbide bit, it's pretty fast and the control and finished results of this tool blow away doing it by hand or with the Collins foot.

I learned two more things about working with crown moulding. On outside corners, I have found it best to make the corners on the ground and install a finished corner that is perfect. It's just too tough for me to joint boards on the wall for outside corners and get good results. With MDF especially, a hot glue gun forms tight strong outside corner joints and is the perfect tool instead of trying to nail it together.

Also, when I do crown moulding, I do all horizontal turns of the saw with the crown upside down and leaning against the fence of my compound miter saw. Personally, I built a taller fence for my miter saw so that I can lean crown upside down in the saw and easily hold it at the correct angle leaning against the fence. It really speeds things up. Also, its true that most corners are 90 degrees, but when you get one that isn't that is an outside corner, you can't keep the joint tightly together if you don't adjust your miter to the actual angle of the corner. The most important thing about doing corners other than 90 degrees is to check that your saw is square before trying to cut anything other than 90 or 45 degrees. I adjust the fence and the tilt of the saw to make sure I get 90 degree readings against the saw before starting. I have found that saws out of the box aren't in good enough alignment to ensure tight joints.

Comment from contributor E:
Here is how I take the guess work out of finding the exact length to cut crown, no matter if I am putting up my first or last piece, or cutting miters or copes at the corners. I get a scrap pice of crown around 16" long, and cut the right and left corners on each end to fit the existing corners. I place a 6" mark at each end on my test piece, from what will be the longest point, and place it into position and transfer each 6" mark to the wall, one at each end. I measure from wall mark to wall mark and add the two 6" lengths (12")to get an accurate (to the 1/64") total length.

Comment from contributor F:
Okay, you want to be quick? Do you have a deadly eye? I install 40 miters a day in and out. I charge 20 bucks per corner. Screw the per foot charge - anyone who has done a column or returned to a a/c difuser will tell you why.

Buy a Hitachi 10" with laser and the Hitachi work station. Read the Hitachi manual and learn to cut crown flat. I don't care if it's 5 1/4, 7 1/4, blah, blah. First, cut your long runs square. Use the drop off a piece over 3 feet, preferably as a tell stick. You will need several per job for ins and outs. Cut a perfect (Hitachi makes this easy) inside 45 / 22 1/2 and cope same with outsides, just no cope (duh). On your copes use your great grandfather's coping saw. In the absence of that, buy 3 of those cheap ones - I go through about 10 a year. Never can have enough blades. Hold the coping saw right (the end of the handle should rest inside your palm) - this isn't a rip saw.

Okay, so you can cope now. Take a mini grinder with 60 grit (this takes practice, but it's not too hard) and wham - you're done. Measure wall to wall, not your long runs details to detail. Oh, the tell sticks help you make micro adjustments from true 45/ 22 1/2... I love doing 8 sided trays and double trays - that's money, honey. 16 corners times 20 and you can bake them in 3 hours or less. Who says lawyers have all the fun?

Comment from contributor G:
I make a pretty good living installing crown, base and case. Crown molding is my best money maker at $4.00 minimum per foot, no charge per corner, extra for vaulted ceilings.

There is no trick to installing crown, once you know the basics. Measure the length of the wall and add 1/16. Always check the angle of the corner with an angle finder. I use the DeWalt 708 CMS for all my jobs and have found it great.

There is no such thing as a perfect corner, especially in tract-homes. 92/88 degree corners are common, and if you know the formula for the compound cut, your job is simple.

Comment from contributor H:
I have found the best and fastest way of coping, not just crown but any trim, is to use a Bosch hand grinder with 60 grit sanding disk. Just make your inside corner cut the same as you would for a normal cope, highlight the edge of the miter, then use the grinder. It will make your cope cut in seconds.

Comment from contributor X:
Regarding drywall corners that are built up out-of-square, I always cut a scrap piece of the moulding square on both ends as a banger block. Whack it in both directions to flatten the texture or built-up mud and establish good corners to measure and install to. Another useful technique is to nail together inside corners on the ground and lift up as a unit. The cuts coming off the ends of these premade corners are more easily adjusted than fighting one corner or the other. I have done this in many areas - in large spaces you can set all four corners and then fill the middle with the appropriate cuts (works best on paint grade, and uses up a lot of scraps).

Comment from contributor V:
One mechanical method of installing angled, wall to ceiling, paint-grade material with a miter saw is first to:

- Measure and rip a beveled back rest that will lay against the fence, holding work secure and hopefully safe (in the position it will be mounted). This will vary with width of mould. ALL mould cuts will be made with the top edge down.

- For an inside left-hand corner, the blade is at 45 degrees and swung to the right-hand side.

- The mould is also on the right side, top edge down.

- Left inside corner: Blade left, mould left, top down.

Outside corners:
- Right hand - blade right, mould left, top edge down.
- Left hand - mould right, blade left, top down.

If rooms are longer than material length, add 45 degree miters for overlap joint. Always do left or right ends the same and add paintable caulk/putty to all joints prior to assembly. Wipe excess with damp rag.

Comment from contributor L:
One of the most important aspects of installing crown molding properly is knowing the correct profile/angle the molding sits in relation to the wall and ceiling. In other words, how far down from the ceiling on the wall the crown should sit and how far out from the wall the crown projects on the ceiling. Once you have these projections, a good pair of crown stops added to a professional compound miter saw make a huge difference. With the crown stops, you can position your molding on your saw exactly as it should sit on the wall. The only trick is, when you make your cuts, you have to cut the crown upside down and reverse the cut. As far as coping goes, with some practice, you can remove most of the wood on a table saw and finish off the more intricate cuts with a coping saw. Following these simple steps will produce excellent results on a consistent basis. Adjustments to deal with out-of-square, -level and -plumb walls, corners and ceilings are all part of the installation process.

Comment from contributor M:
I have installed hundreds of feet of crown. I usually start with a coulple of 24" pieces cut opposite angles for a template. I then find the correct angle for every corner in the room before I make the first cut. This helps the saw man and or anyone else setting my saw. I use a Dewalt sliding compound mitre. One job and the thing is paid for. Use your own judgement about making copes. I once had to cope 12" cherry on an 18' ceiling. Coping is much tougher than mitre. If you get your angles right with templates the first time, you will not spend your day adjusting your cuts. I usually add some blocking at all corners, and use a glue like Gorilla to secure mitre joints. I think the other guy was close with his $4.00 per foot price. I usually charge at least $10.00 per foot for installed and painted crown.

Comment from contributor I:
I am shocked at how difficult everyone is making crown install. I have been installing cabinets for 27 years in Los Angeles. Dry fit as you go and adjust degrees to fit. I adjust somtimes in one 1/4 of one degree to make a closed fit, so dry fit and adjust first and get three or four pieces ready ahead of the nail-up. You do not have to cope, miter, and try to nail inside pieces together, then put them up.

Comment from contributor Y:
There is a new tool out that helps cope crown molding. It's called the EasyCoper. It is a jig that allows you to cope the crown molding with an electric jigsaw. You slide your molding that has been mitered in the miter saw in the EasyCoper and then take an electric jigsaw and follow the contour.

There is still some skill in following the contour, but the jigsaw is positioned in such a way that it gives you an undercut or back cut that is always consistent and you never have to take any more off the backside with a grinder, rasp, or whatever method is used. It's simple and easy.

Comment from contributor U:
I too am surprised at how difficult this is being made. Coping crown moulding is just another part of the job that first rate carpenters should be able to do quickly. Most cabinet crown installations should not even need the cope if all is installed square, level and plumb.

As for crown installations on wall to ceiling applications put the cope where you will not be looking directly at it when you enter the room. Also a right handed carpenter will prefer a left handed cope and vice versa. This is due to the angle of the back cut and how the coping saw is held. I am aware of a coping machine but you would have to install thousands of feet of crown for a machine of that nature to be financially feasible.

A grinder will also do the trick but it is loud and dusty. Large crown might call for the hogging method and a grinder, but for most of us 4 1/4" crown can be done efficiently with a medium toothed coping saw. Make sure to set the saw blade so it cuts on the push stroke. This is a method that will make things quicker and cleaner.

Comment from contributor R:
I find that coping corners gives the best result on most crown jobs. After setting up my saw for inside corners I don't change it. I always start from the left and work around the room. I put up a scrap piece in the corner I start from and cope the adjacent piece and extend to the other end of the wall adding 1/16 for snap. When I get back to my starting point I remove my scrap piece and fit my square end under my coped piece. By doing this I only have to cope one side of the crow on each piece.

There are a few new tools or should I say aids that make coping much easier. There is even a power coper available if you want to spend the money. Many of the new aids are inexpensive and believe me make your job much easier. One is a guide system called EasyCoper. You can master this set up in about 5 minutes.

Comment from contributor F:
I have read all the posts and am a little confused. I have been trimming homes for 15 years. This is not rocket science. I measure my room and cut all my pieces: 1 square to square, 1 piece with right hand cope, 1 piece with a left hand cope and the last piece coped on each end. I cope all of my cope cuts with a Bosch jig saw using a 24TPI blade free hand and get perfect copes.

I take all of the pieces to the room and hang them. I hang the square end first, then left cope piece, and then the right cope piece next, always leaving the ends of each piece of crown hung and not nailed 3 to 4 feet from the end to allow flexibility when tying in a coped end to it. Lastly I put in the piece of crown that is coped on both ends and nail it off. The time it takes to measure a room, cut the crown, cope the crown and hang the crown is 1 hour. I charged $10.00 per corner inside and outside and $10.00 per splice if the room is over 16 ft. So a square room not over 16 ft. would have 4 corners at $10.00 per corner = $40.00 – that’s $40.00 per hour. This $20.00 per corner + $3 to $4 per foot is high, and taking a half a day to do one room is way too long.

Comment from contributor K:
I agree with Contributor F. The only thing I could add would be this is that every crown has a degree of bevel or angle. 41/4-41/2 is 38 degree as is 31/4. What this means is that there are settings on compound mitre boxes. For crowns in the range I mentioned you use 35 degrees on the saw table and 33 degrees on the arm bevel gauge. The use of a hand held jig saw is best because you can get more than a 45 degree cutout.

One last thing - try using a coped piece left and right, leave unnailes about 2-3 feet from corner and use your coped pieces to adjust you setting on the wall. Lastly, if you have a long run 10 feet or longer add 1/8 inch and bend crown in the middle and allow it to snap into place.

Comment from contributor W:
I am a professional cabinet installer, and spend at least one day a week installing crown. I use a Dewalt compound mitre saw with crown stops, and miter all cuts. All my crown is pre-finished an must be light tight, so I use a pair if test pieces to fine tune the angles, and then super glue them for a fast set. If the crown is heeled, and mine usually is, I pre drill it and screw it down from the top if there is clearance. If not I use a #1 trim head screw up from inside the cabinet. I dress all joints with color putty, which I blend to match. I charge $45 per 8' length. Each length takes an average of about 30 minutes.