Shelf Span

[Dan McLaughlin]

I need to build a small stereo component cabinet with two shelves that need to span about 60 " and 18- 20" deep (it needs to fit in a specific spot). The maximum weight per shelf will probably be 60-90 lbs. I was going to use 3/4" plywood with a hardwood edge in both front and back. Most of the span tables indicate a maximum length for 3/4" plywood of 36" to 42" for books, which probably weigh more than the components I plan to use. I was wondering if anyone has built component shelving with that kind of span - what material did you use? Any other suggestions? 6/4 red oak looks like it can take a span of 60" without a problem but that might throw the size of the cabinet (height wise) out of wack. Of course, that might be easier to deal with than shelf sag. Thoughts from the community?

[Jamie Buxton]

Well, I sure wouldn't attempt to span 60" with a single thickness of plywood. That's mostly because it will sag too much for my eye, and partly because the plywood itself may be curved when it comes from the store.

Here's what you do... Go buy the sheet of plywood you're going to use for the shelf. Cut it approximately to size. Support it at the ends and put those two components on it. Put a little extra weight, just for grins. Now look at the sag. If you're okay with it, go ahead. If you're not okay with it, add support until the sag gets small enough for you. Then design your cabinet.

You'll get lots of opinions on this board, but there's nothing like reality.

[Bob Winkler]

That's a longer span that I would do unless I used solid wood edging front and back that was at least 1 1/2 " wide.

As an alternative, solid oak shelving at least a full 1" think is pretty strong. I have a 4' long shelf with a 1" thick oak panel supporting a 200# HDTV right now. No sag after 2 months:)

Another alternative is a torsion panel. I built my closet organizer this way and it is very strong. Use 1x frame sandwiched between 1/4" hardwood plywood. The plywood skins are glued to the frame (my framework was 1x4 doug fir from Lowes)and make the whole assembly incredibly ridgid. The edges get covered with solid wood edging.

Just my thoughts. Good luck. Bob

[Dan Gill]

Think about adding a 1 1/2 inch solid edge on the front, and perhaps on the back as well. That will stiffen it considerably. You can also fasten the back of the shelf to the back of the cabinet in some cases.

[John Miliunas]

Dan, I'm with Bob on this one. Well, at least, the torsion box part of it. For that long a span, I believe it would be the strongest option, plus it wouldn't add a whole lot of weight to the unit. Just MHO.... :cool:

[Greg Tatum]

Do the shelves have to be 60" long or just fit in a 60" space? Why not use 2 30" shelves with a face frame to add support? How about 2 lengths of angle iron with a plywood top and hardwood edge to cover the iron? Or a torsion box. Whatever you choose, make sure that you get to buy a new tool to do it with....maybe you need a .....welder ;)

Greg