Leg sectional dimension is primarily determined by joinery. Since the
legs are mostly in compression, you only need a very small section to
hold 200 lbs. But you do need a wide rail-to-leg contact to reduce
racking stress on the legs.
For my slat beds, I use 8/4 planed down to about 1-3/4" thickness, and
about 2-1/2 to 3" wide. This leaves plenty of wood around the 7/8"
mortises for the rail tusk-tenons. Structurally, nominal 2x2 (1-1/2"
square) would probably suffice, but it would look funny.
Rails are more critical, because they must support a dynamic load across
a long span without twisting or bowing (which could cause the slats to
fall out). Dimensions depend on the wood you are using; with oak and
ash, I've had good results with 7/8" rails 5" or wider.
I don't build beds of softwood. My squire made a rope bed of fir, with
4x4 posts and 2x6 rails (tenoned full thickness through the posts). The
rails held up fine but the posts split above the mortises, from
The biggest thing is to design and cut the joints (side rails to legs,
headboard and footboard to legs) to resist racking. If those joints
have any play at all, the mortises are likely to split no matter how
thick the legs are.
p.s. You can see the design I use here:
On 1/5/2011 9:15 AM, perriscott wrote:
> I am new to this list and I am seeking advice from more experienced woodworkers than I. I have looked at photos and the Files section, but have not found exactly what I need...
> I am trying to work out a variation of a slat bed that breaks down for easy transport. I have found numerous versions of "full" size and even "queen" size-- it is a simple matter to downsize for a "single/twin", however, I have not been able to locate a size for legs.
> The bed has to support under 200 lbs, so 6"X6" is not _necessary_ but would no doubt be sturdier in the long run. My proposed Materials List includes (so far) 2X4's, 1X6"'s& 1X1" furring strips and 1/4" to 1/2" dowel pegs.
> If anyone can suggest a different list of materials or construction method I would be grateful. This bed will (ideally) be permanently set up for home use as well as event use, so it needs to break down and set up without losing integrity over time.
> Thank you in advance,
> Elspeth McArran,
> Regiment de Hepburn