What I am calling a shelf stretcher is the shelf shown in the attached picture of an ottoman. The best I can come up with is to put a 1/4″ deep stopped dado in two sides of each leg and let the shelf float there. I am reluctant to fasten it in the dado because of expansion and contraction possibly weakening the upper joints. The wood is cherry and the width is 15 1/2″ so I figure I need to allow for about 1/8″ of movement. If I let the shelf float, I would need to allow for 1/16″ of slop width-wise in the dado stops which bothers me aesthetically. For strength, I would rather fasten the shelf in place. Any suggestions on the best way to attach the shelf? Am I worrying too much about the wood movement? BTW, is there a proper name for such a shelf in a table?
…tom
Replies
I too would be concerned about wood movement in this case and therefore would not use a "simple" solid wood panel. One alternative would be to breadboard the ends and have the breadboards fastened to the legs in whatever manner you prefer. A frame and panel solution would also work. Finally, there's always cherry veneered plywood.
Austin,
I generally dado a slot diagonally across the back corner of the legs. Make a cradle for the tablesaw to hold the leg with its inside corner downward, and make the dado deep enough to support the shelf- 5/8'- 3/4". (If only 4 legs, it is easy enough to make the cuts by hand.) Clip the corners of the shelf off to fit; they can be attached with a screw in a pocket on the underside of the shelf driven into the leg.
Movement ought not be an issue, as you say it might be 1/8", meaning that each leg gets sprung only 1/16" in or out over the course of the year.
Ray
Would it be feasible to only attach it to 2 legs and let the other 2 float?
I have considered that but I don't gain any strength on the floating side that way. I could gain some strength on that side in one direction by using a sliding dovetail rather than a dado but the other direction would still be weaker.
The possible movement would be closer to 5/16" in many climates so you should use a design that allows for expansion and contraction.
I would build the shelf as a frame and panel with a simple square edged rabbet around the edges of the panel to bring it flush with the top of the frame with the minimum visible joint.
John White
Shop Manager for FWW Magazine, 1998-2007
I use that exact type of shelf on many built in tables used in my remodels and many craftsman style furniture pieces.
Personally I like to chisel out a tight fitting notch for the corners of the shelf to sit in allowing for 1/16" of movement per foot of shelf width, which is generous given the climate in Boise doesn't have large humidity swings. The notch can be snug on the end grain side since a board won't grow in length much.
You'll find the joint between the legs and shelf are not brightly lit by most indoor lights and a minimal gap will be hardly seen by most.
If you are in an area with large humidity swings the corner of the shelf can be cut back as much as needed--say 1/4" (with the shelf cut just touching the leg) and the visible gap is nothing. Can't explain it better, but it allows the shelf to expand without any gap.
I've also notched the shelf completely around the legs and used 1/4" shelf pins to support it. The expansion can be checked and adjustments made to the notch as needed for your climate. This is a good solution if you might move the shelf or whatnot.
The key is knowing what the wood movement in your situation will be. Some people have humidity controls on their hvac so they can keep the humidity very close year round, or they can run the humidity up and down like crazy based on their moods and it will play heck with the levels.
I've also seen the shelf undersized so it doesn't make it to the legs and supported with metal dowels that exit the corners of the shelf and into the corner of the leg with a gap of 1/2" or so. The dowel can wobble in the holes a little and accomodate large swings in movement. The holes for the dowels can be drilled extra deep to accomodate a small spring so the dowels will snap into place.
Best of luck and I love the look of that type of shelf!
Beer was created so carpenters wouldn't rule the world.
Hi Tom,
I too would be concerned about strength, but I think if you combine two of the suggestions given here, you can cover all your bases.
For seasonal movement, I like the suggestion that you notch each leg and cut your shelf corners to fit such that you allow for seasonal movement only across the grain of the shelf. The small seasonal opening that you get on one side will definitely not show.
I would then incorporate the suggestion that you use pocket screws from the bottom to add strength and prevent catastrophic damage when someone kicks the leg as they walk by or moves the ottoman while their feet are on it - the usual way, by the way.
However, when installing the pocket screws, I would make the pockets oval shaped to allow seasonal movement, and not tighten them down too terribly tight.
Then you have both concerns covered.
Make sense?
Mike
To everyone that has made suggestions, thanks. I am still considering my options.
I am leaning in the direction of making the shelf by veneering cherry onto a plywood substrate and edge banding it with cherry. I know plywood is dimensionally more stable than solid wood but it is still made of wood and it seems it would still have some expansion and contraction. Is it something I should worry about with 16" of width and 22" of length?
As far as attachment, I want a 1/4" reveal from the outside of the legs so a diagonal dado or a notch in the leg for the corners would remove too much wood from the leg. I am leaning to notching the corners of the shelf to fit into 1/4" deep stopped dadoes on the legs like I had originally thought of. If I don't have to worry about dimensional changes, I am thinking of gluing the shelf in place and pinning it from the bottom with brads. If wood movement is still an issue I will probably use the pocket hole suggestion or go with the frame and solid wood panel suggestion.
Any final comments before I start cutting wood, especially wood movement with plywood?
...tom
When it comes to wood movement it is safe to design and build assuming plywood has none. If that were not the case then edge banding all four sides of a ply panel with solid wood would be a big no-no...right?
Good point. I guess the plywood expansion is roughly equal to the linear expansion of the edge banding and we typically ignore linear expansion.
The great thing about woodworking is that there are so many "right" ways to accomplish the same thing.
Give us followup in a year and let us know how it turned out.
Mike
Another design option that came to mind would be to use stretchers between the legs with mortice/tenon joints, and then attach the shelf to the stretchers, with no direct attachment of the shelf to the legs. An "X" pattern for the stretchers would mostly hide them from view, and would provide long-grain support between the legs. The shelf could be notched to fit around the legs as desired, with spacing dependent on the wood used for the shelf.
I made two of these tables last year, and mounted the lower shelf in diagonal dados in the legs - blind nailing from the bottom. I've used this technique on other tables over the years and they have all held up just fine.
Oops, forgot to attach the picture. See next post. - lol
Edited 8/16/2009 9:45 am by Dave45
Must be time for more coffee.
Very nice table! Since I am trying to have no more than a 1/4" reveal from the outside of the leg, I would need to remove almost half the width of the leg for the diagonal dado. In your experience, would you be comfortable removing that much?
...tom
Nope!!The dado weakens the leg and the deeper the dado, the weaker the leg.It would take some planning, but if I just had to have a reveal that small, I would limit my dados to ~1/4" and make my lower shelf to fit in them. Then, I would dry fit the shelf using band clamps and make edge pieces to give me the desired reveal. If you keep track of the shelf offcuts, you should be able to get a grain match that would make your edge joints virtually invisible.
Good suggestions. I hadn't decided on the thickness of the edge banding anyway so I will make the shelf undersized to fit shallow dadoes and make the banding thick enough to give me the reveal I want. I'll try to use the off-cuts like you suggested too. Thanks.
Glad i could help, Tom. Post some pics when you're finished.
A couple pics of the whole set.
So how did you decide to "attach" the shelf?
For the shelf, I used a plywood core and applied cherry veneer and edge banding. I then cut stopped dadoes in the legs, about 1/4" deep and cut coresponding notches in the corner of the shelf. I blind nailed the shelf to the legs from the bottom.
It was pretty much the idea I started with but I switched to a plywood core to deal with wood expansion. Other suggestions would have worked except I wanted a 1/4" reveal on the outside and most of them would have removed too much wood for that.
Thanks for all the suggestions and I will keep them in mind for future projects.
...tom
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