Need options for a solid-wood cabinet back

[Andy Pratt]

I'm making a small wall-hanging jewelry cabinet roughly 32HX24WX6D and I'm trying to decide how to build the back panel.

The entire project will be made from solid wood, and the back panel will have multiple screw-in hooks on it to accomodate pieces of jewelry.

My normal method - a standard raised panel - is not ideal as it will reduce the useable area for hooks (can't use the tapered portion near the panel edges), and has the potential to flex or rattle over time. I would be using spacer barrels, but this will be a highly noticeable area if it ever did start to allow movement.

I have read various options, and it seems like a ship-lap or T&G back panel might be appropriate, but I have not used this style before. Here are my questions:

Is each T&G/shiplap board affixed through it's mid-width point to the case, and allowed room between it and the next board to expand/contract?

If this is the case, what is a reasonable size board width to use for my project (can be up to 8" given my stock), and how visible are the edges when the board is very dry?

Hopefully I've described this adequately, I'm open to any other ideas given the constraints of solid-wood and maximizing hook space.

The material for the backs will be 3/4" hickory, case is the same.

Thanks,
Andy

[Jim Becker]

Andy, ship-lap or T&G is typically used for cabinet backs when solid wood is desired. The joints are not glued and the back either mounts in grooves or is pinned with single brads that allow movement seasonally. If you are pinning, you can leave some play in the joint to accommodative the movement...check on the figures for the particular species you are using to calculate what that might need to be. It's just like figuring the same for inset doors to determine the ideal size that has an acceptable average gap, but will not bind when the piece shrinks.

[Lee Schierer]

As Jim says the separate pieces are pinned in the center. I've used small screws to do this without any problems. In my area right now my shop is very dry so the wood is as dry as it will ever get. I would look at the expansion figures for the width of board I plan to use and leave at least that much gap between each board as they are assembled now. Then in the summer when the humidity goes up and the wood expands it will have some place to move. Other wise you can blow out a side joint (DAMHIKT). By leaving the gap between each board and only anchoring the center of each board the edges of those boards can move.

I made a dresser from hickory (actually two dresssers) and I glued some drawer supports cross grain directly to the 3/4" thick side panels. The dresser was made in the summer. One winter evening we heard a loud pop in the bedroom. We didn't find the problem right away. A few days later we heard another pop, further investigation showed that the side panels had split top to bottom on both dressers. I was able to permanently fix the problem, but it was a tremendous amount of work.

[Ed Labadie]

I've used solid wood backs on a couple of projects with really good results. I dadoed the sides to accept a flat panel and used spaceballs to keep it tight but allow for seasonal wood movement.
Both back panels were slightly under 1/2" thick to fit in a 1/2 dado. Pin the center to keep the movement central.

I also "set" the spaceballs in a dab of glue to keep them from moving during assembly. There are strip type "fillers" that would have worked better.....maybe next time. :o

Ed

[Andy Pratt]

Jim/Lee thanks for the confimation on the method for T&G or shiplap pieces, I'm sure I can find the data for Hickory in Hoadley's book, so I may post my calculations after that to make sure I didn't do it wrong.

Ed, althought I haven't looked up the data yet, I am worried that the spaceballs won't allow for enough movement in a (20") glued panel to keep it snug and not exert too much pressure on the sides. Even if I lay everything out perfectly, I can't imagine getting more play in the rubber than about 1/8" (1/16" on both sides). I'm using the 1/4" spacer barrels from LV, do the ones you are using allow for more play than these, or do you think I'm actually getting more play than I expect?

Thanks,
Andy

[Ed Labadie]

I used about for 1/16 compression on the spaceballs, so maybe end up with 1/8 per side at the most.
Both cabinets were 1/2 sides & back, you are using 3/4 sides, so the dado can be made deeper, 1/2" if you like.

Just a thought.... use the spacers on top & bottom only, go 1/4-5/16 deep engagment in the sides (1/2 deep dado), pin the center & don't worry about it. The panel won't rattle since it's not a door & the top/bottom fit will hold it tight.

Ed

[Andy Pratt]

I did the calculations and it looks like i'm looking at around 1/2" of expansion on a 22" wide panel. It varies from 1/4"-2/3" based on a number of variables. I have a vertical support going through the center of the cabinet interior anyway, so I think my solution will be to divide the back into two smaller panels. That way I should have only 1/4" to contend with in either, which leaves me needing only 1/8" of play in each dado, which seems a little more reasonable. Ed, I think I'll try your idea of leaving the spacer barrels out of the side portions, I'm sure with the friction in the top it will hold them fairly securely. If I make a flat backed raised panel and put the flat portion toward the cabinet-interior then I won't lose any hook space.

Seems like this will be a pretty good solution to the problem, without having to rip my boards into smaller pieces and T&G/shiplap each, thanks for the help working something out on this. I like the T&G/shiplap style, and I think I'll try it sometime when I'm using narrower stock.

Thanks,
Andy