Chestnut Tool

Clam
Clamps

1-800-96Miter
(1-800-966-4837 )
P.O. Box 812
Holden, Maine 04429

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Sept. 24, '06

 

 

 

 

 

 

 

 

 

 

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Building Radius Cabinets - A Photo- Essay

 

 

 


 



 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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Building Radius Cabinets - A Photo- Essay

"Installing Crown Molding"

"Coping Crown Molding": A Video


A Woodworking Video: Coping Crown
courtesty of:
Clam Clamp Miter Clamps
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Perfect Miters ......Fast
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Installing Crown Molding efficiently requires cutting crown molding then coping crown molding inside corners. The following woodworking video may save you considerable time when installing crown molding, simply by changing the blade you are using when coping crown molding prior to installing crown molding.

Sorry for the redundant, meaningless drivel above. I know you aren't an idiot, that was for the benefit of the search engines whose designers seem to be. Without the gibberish you may never have found this page. The remainder of the text will not be gibberish to a trim carpenter and I believe it worthwhile to read before watching the video.

High resolution (41 MG): Video Coping Crown Molding with a jig saw. (8 minutes)

Low resolution (14 MG): Video Coping Crown Molding with a jig saw. (8 minutes)

I would recommend that you download the higher resolution video, even though it could take 10 minutes on a DSL connection. Go pop a beer or something while it's downloading.

For this video I selected a crown with a 45 degree spring angle (the angle that the molding forms with the wall on its way to the ceiling) because it is generally much more difficult to cope than the 38 degree crown typically sold in lumber yards and discount houses.

As a crown molding profile approaches a horizontal plane it must be thinned down to the extent than it's thickness would equal one molecule if its mating piece of crown is one molecule above a horizontal plane. Otherwise it will not fit. If the profile dips below the horizontal, then it is not copeable. Most of the uncopable crowns I have used were products of the imaginations of people who had never installed, or even seen installed, a single stick of crown - namely, interior "designers" and architects.

Since 45 degree crown is already starting off 7 degrees closer to the horizontal than "standard" 38 degree crown, it generally needs to be radically thinned in 2 places on the profile in order to fit. One purpose of this video is to point out these sections and illustrate just how thin "thin" is.

Crown molding is best cut on a standard chop saw using the traditional "upside down and backwards" technique, despite what the manufacturers of sliding compound miter saws ( "SCMS" from now on) would have you believe.There are a number of reasons for this. The principal ones are as follows:

1. To flat cut crown on a SCMS two angles must be set instead of one, the miter angle and the bevel angle. The scale for setting the bevel angle has graduations so close together that it is not possible to get a truly accurate setting - assuming that you even know what it is. Regular chop saws require a miter angle only which has graduations a long distance apart, allowing for accurate setting. The bevel angle is effected automatically by the position of the crown molding in the saw itself.

2. A "perfect" cope will only fit perfectly if a number of conditions are met. The molding coped must be identical in every way to its mate -ie. in width, and in the amount of cupping present, and in the exact same position as its mating piece with regard to the spring angles of both. And the chop saw cut that establishes the coping line must be exactly right.
If the piece to be coped into is rocked up an eighth from the "correct" wall height for any reason (low adjacent ceiling joist, adjustment to maintain cabinet rail reveal etc.), the spring angle has been changed. With the standard chop saw, the crown to be coped can be simply rocked down an eighth lower on the fence and cut - no other adjustments necessary. This will establish a "perfect" profile match with the crown already up. To do this with a SCMS requires a complete re-calculation of both the miter and bevel angles prior to cutting.

3. With outside corners, the intersection marking method can be used with a standard chop saw simply by rocking the molding's position in the saw until the intersection marks line up. Again, this would require a re-calculation using a SCMS.

4. Most 45 degree crown will be at least slightly cupped by the time you get to use it. I believe this is because it tends to be wider than the "standard" stuff and often has more pronounced detailing - meaning it has been milled from thicker stock. Deeper and more detailed milling on the face causes it to cup in that direction. The back then becomes like a cylinder (with a very large radius of course). This does not matter when it is cut traditionally since the back of the molding is not touching anything.

But when cutting on an SCMS, the molding is sitting on its cylindrical back while it is being cut. The saw operator has to guesstimate that he has each piece in exactly the same position before cutting and while cutting. And he has to be right every time or else the cope won't fit. Or, he has to use shims under each edge of the molding extending right up to blade, so the middle of the back of the crown molding does not touch the saw bed and cause the molding to rock. The only way to do this fairly efficiently, is to make up a sliding bed for the SCMS such as the one Gary Katz demonstrates in his video series on "Mastering the Miter Saw". However, in that video, Gary is not cutting crown. You can bet that he cuts it traditionally when doing it on a job.

You will notice in the video, that the cope I do won't fit while it's still clamped to the bench because the clamps have straightened out the crown while it's being coped. But once it has been released from the clamps and has returned to its previous cupped state, it fits its likewise cupped mate.

Prior to installing the coped piece, I generally back plane the top edge of the crown with a power plane from the end back an arm's length. This way, if there is a low joist near the joint, or if the mating piece is rocked slightly, the coped piece may still fit. But even if it doesn't, I have removed enough material that a block plane should be able to quickly scribe in the coped piece. If you have a Makita power plane, you may want to check out this video to vastly improve it's performance. Makita Power Plane.

 

More on installing crown molding can be found in the Installation Section of "Building Radius Cabinets - A Photo-Essay". Here is a link directly to those pages. They load quickly. This takes you back up to the Coping Video Link.

 

Woodworking Video Index
10 Total so far. Newest one 24 Sept 06
Check back ocasionally.

I regret that all the woodworking videos here require DSL or Faster connections to view. Their nature requires decent resolution to be worthwhile to the viewer. Anything less would be a waste of your time. Thank you.

1. Video How much pressure? ( 7 MB, 2 minutes 50 seconds )--------Demonstration of the pressure that Clam Clamp's exert on miters as well as a few gluing tips.

2. Video Drawing an Ellipse ( 19 MB, 640 x 480, 3 minutes 48 seconds )
Video Drawing an Ellipse ( 10 MB, 320 x 240, 3 minutes 48 seconds)
This is the first of three videos dealing with ellipses, and shows how to draw them simply and perfectly without strings or formulas.

3. Video Making a jig to cut ellipses. (38 MB, 640 x 480, 7 min. 40 sec.)
Video Making a jig to cut ellipses. ( 20 MB, 320 x 240 , 7 min. 40 sec.)
As usual it takes a long time to describe how to make anything and this jig is no exception. However, it is both simple and fast to make with stuff you already have in your router box.

4. Video Cutting an Ellipse (with a router and jig) ( 6 MB, 1 minute 15 seconds)------ This is the final video in the ellipse series, and as you can see, it takes much less time to cut the ellipse than to describe how to get started on it.

5.Video Coping Crown Molding ( 41 MB, 8 minutes 18 seconds)
Video Coping Crown Molding (14 MB, 8 minutes 18 seconds).
Note: These two links will take you to the top of this page where the link to the video actually is. The reason is that there is a lot of text regarding coping that you may want to read before watching the video.

6. Video Makita Power Planes. (20 MB, 3 minutes, 640 x 480)
Video Makita Power Planes. ( 10 MB, 3 minutes, 320 x 240)
This short video shows how to modify Makita Power Planes to get a 3/16th or more depth of cut per pass for more versatility.

7. Video Slotting casing for Biscuits. (25 MB, 2 minutes, 640 x 480)
Video Slotting casing for Biscuits. ( 4.5 MB , 2 minutes, 320 x 240)
This short video shows the fastest way to slot casing that I have
found, without getting cocked slots.

8. Video Tweaking a Biscuit Jointer ( 7 MB, 2 minutes 57 seconds)------- How to widen the biscuit slot on biscuit jointers, and why this should be done. Tips on biscuit jointing and clamping MDF casing.

9. Video Plugging and un-plugging screw holes. ( 8.5 MB, 4 minutes 40 seconds).
Video: Plugging and un-plugging screw holes. High Resolution (38 MB). Same length.
Tips on plugging screw holes and removing the plugs when they break off down in the hole.

10. Recognizing Un-copable crown molding. (5 MB, 3 min. 23 seconds.)
Recognizing Un-copable crown molding. ( 25 MB, 3 min. 23 seconds.

 

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