How to Secure Floating Panels

Using spaceballs versus pinning panels at top and bottom center points. January 22, 2006

I am constructing an end panel for a dresser using solid maple boards glued up and installed vertically. The end panel will be sandwiched between the front and back legs of the dresser (20" in depth). I'm concerned about wood movement from front to back (across the 20" dimension). Any recommendations for how to join the panel to the front and rear legs? Dado with Spaceballs?

Forum Responses
(Architectural Woodworking Forum)
From contributor C:
I'd put some mortised rails on the top and bottom. Make it a floating panel. On the plus side, it would stiffen the whole assembly.

From the original questioner:
Thanks. I should also point out that the end grain of the end panel will be attached at the top to the underside of the dresser top (or frame rail) and, at the bottom, to the stretcher.

From contributor R:
Spaceballs don't work - they go flat like a tire. Not to mention the fact they take up space in the frame that would be otherwise available for expansion of the panel. A better method is to center the panel in the frame and pin it in place, two pins centered top and bottom. This keeps the panel anchored in place but allows for equal expansion and contraction in the frame. It's cheaper, too.

From the original questioner:
Excellent point. Thanks for the suggestion on the pins. That will likely solve one of my other concerns - how do I keep this end panel from rattling in the rabbeted channel in either leg?

From contributor G:
Spaceballs are supposed to go flat as the panel expands. Then when the panel shrinks, they expand. Most of the space they take up should be empty, anyway, to allow for panel movement. They do an excellent job of eliminating rattle. The time it takes to center and pin a panel more than offsets the cost of the Spaceballs.

From contributor R:
I understand how Spaceballs are supposed to work. I had occasion to pull a number of panels apart that had been in the field for a bit of time, and the Spaceballs had turned to pancakes and stayed that way. I find it quicker/easier to shoot two pins in the back of the frame than stuff it with little balls. I would not argue any significant difference in time either way. A proper fit between panel and groove will take care of rattle.

From contributor T:
I use Spaceballs and think they work fine. My panels are 1/4 undersized all the way around.

From contributor E:
I pin 'em at center, top and bottom, from the back. More than one way to skin a cat.

From contributor F:
I see a couple of ways to deal with the solid wood movement. In one case, since the dresser sides are solid, any other planes that attach to it can be solid as well. For instance, if the dresser has a bottom that is 20" deep, if it is solid wood and the cross grain runs in the same direction as on the sides, they will both expand and contract together, while the legs can be solidly attached to the sides and they will just go along for the ride as the sides and bottom shelf move with the seasons.

Another way, as suggested, is to use frame and panel construction. The vertical members of the side frames can be fastened solidly to the legs while the panel floats and is either pinned at center or held snug with Spaceballs.

From contributor P:
How about finishing the panel first and letting nature do her thing!

From contributor D:
I've used Spaceballs and I've pinned. Either way works great for me; no problems in either method. Pinning in hickory leads to splits in the wood, so when it comes to hickory, I use Spaceballs.

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

Comment from contributor M:
We use Space Balls exclusively and have for a number of years. If anyone takes a door apart and finds that the balls have flattened that would be an indication to me that more balls should have been used. It would be like putting two tons of cargo in a one ton capacity truck and complaining of poor suspension. I have never had a call back for a panel that was not held in place. From out perspective Space Balls perform as advertised.