How to deal with keyed-in top molding for wood movement on a dovetailed case?

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Forum topic by barringerfurniture posted 12-29-2013 07:55 PM 2618 views 0 times favorited 6 replies Add to Favorites Watch
View barringerfurniture's profile


224 posts in 2161 days

12-29-2013 07:55 PM

Topic tags/keywords: question wood movement shaker dovetails spline joint

Hey folks. Happy holidays and thanks for reading.

I’ve been pondering a couple of problems related to wood movement in regard to a prototype bookcase I recently completed. For reference, here are some pics (More can be viewed in my “projects” page as well as my website blog).

So, one regret I have with this piece is that the top molding is not keyed into the case in any way to allow for wood movement. I’m familiar with a sliding dovetail when attaching side molding to a lid, say, in the case of a large chest – where the tail would be routed into the edge of the lid and the socket routed into the back of the molding, then attached – simple enough.

But here, we have a dovetailed top. My first thought is to use a spline joint, glued into the molding, glued to the case at only the first few inches of the front, then shot with an inconspicuous nail or two at the back to hold tight.

What troubles me though, is the idea of a groove for the spline joint (I’m thinking 1/4”w X 3/8”d) cut right through the sides of the dovetails – It seems to me, the spline should be fairly close to the top surface of the case (hence, through the tails) to better insure a tight seem between it and the molding. Nothing would be visible of course, but structurally, it just seems weird.

Has anybody else dealt with this particular situation? Seen a good example of how others deal with it? I see pictures all over, of a dovetailed case wrapped in molding like mine but nothing where I can get a good look at the back to see how the molding it was attached.

Thank for any advice.

-- Scott Barringer, Sacramento, CA

6 replies so far

View Aj2's profile


2377 posts in 2246 days

#1 posted 12-30-2013 05:46 AM

Scott nice looking piece very clean,A cleat nailed or screwd along top of the case is the best way to go.What I do is cut the cleat into segmented sections.after everything is fitted.I keep two fasteners per section.thats how you get past the long grain to end grain expansion problem.a nicely fitting dovetail cleat will need zero glue.The cleat will also be flat on top and dovetail pointing down.
I may have misread you post I confess to doing that often.Anyway nice looking piece very clean!

-- Aj

View barringerfurniture's profile


224 posts in 2161 days

#2 posted 12-30-2013 07:24 PM

Thank you Backbevel. Yeah, after I posted this, I did manage to find a guy online who did exactly what you’re describing. It’s the best idea I’ve heard so far. He had three dovetailed cleats, each bout 2” long. So I guess I’d attach a cleat full length first for line consistency, then cut it, leaving only the 2” sections. Seems like it would be okay to glue those to the case if they’re only a couple of inches each.

Thanks again.

-- Scott Barringer, Sacramento, CA

View pintodeluxe's profile


5970 posts in 3262 days

#3 posted 12-30-2013 07:37 PM

The cleat idea is sound. Although it may add additional challenges to getting a tight outside miter on the trim.

Here’s another idea. Since you have an upper valance, you could attach the side trim with screws from the inside of the case. The front valance will make the screws virtually invisible. Slotting the screw holes would allow for movement of the side panels. That way the trim could be installed as usual, with a glued miter joint. The back of the trim could be tacked on with a brad or pin nailer until the screws were installed.

Good luck!

-- Willie, Washington "If You Choose Not To Decide, You Still Have Made a Choice" - Rush

View barringerfurniture's profile


224 posts in 2161 days

#4 posted 12-30-2013 09:50 PM

Pintodeluxe, that’s another good idea and sounds easier too. But I do like the idea of being able to see the joinery from the back if one were to look for it. Let’s them know it was a tip-top job.

I’ll have to think about it.

Thanks for the help guys.

-- Scott Barringer, Sacramento, CA

View Loren's profile


10477 posts in 4096 days

#5 posted 12-30-2013 10:47 PM

I know the purist approach is attractive. Many customers
may praise the all-joinery approach but won’t want to pay for it.

The screws from the inside are a good idea. If the Shakers
had them I bet that’s what they would have used.

Another way to do it is with something like a 1/2” x 1/2”
square section the depth of the case. Screw it on with
slotted screws at the back. Cut an open groove in the
back of the moulding and glue the parts together. You
can shoot pin nails up from the bottom to hold it tight
while the glue sets or use bar clamps. The customer
can look at the back and see the square block and say,
“oh that’s quality”.

It doesn’t have to be a dovetail to impress.

You could put a little section of dovetail at the end
just for looks. I wouldn’t do it personally though because
I don’t consider that sort of thing honest craftsmanship.

View barringerfurniture's profile


224 posts in 2161 days

#6 posted 12-30-2013 11:26 PM

“oh that’s quality”.

I actually entertained the thought of inlaying a “mock dovetail key” in the back on this one. Yeah, not very honest but pretty funny.

I like screws just fine and may go that route next time. I use slotted brass screws to mount table tops and drawer glides. I think they look pretty classy if they’re clean and countersunk.

-- Scott Barringer, Sacramento, CA

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