There are commercially available metal frames that do the same thing. Sizing a Bed To the sleeper, the most important part of the bed is the mattress. If the bed and platform are structurally sound, the mattress determines the comfort of the bed. To the woodworker, however, none of this is of much interest. The most important thing a woodworker needs to know about a mattress is its size, and this is a big deal indeed.
Mattresses vary in size more than enough to cause big problems for the woodworker.
The standard mattress sizes I've encountered are listed in the chart on p. 10. I use them as a rule of thumb because variations in size are quite common. I've come across mattresses that were as much as 1 in. The lesson here is that it's very important that you measure the length and the width of the mattress you'll be using with the bed. But don't make a wooden bed to fit a slightly undersized mattress because a bed should outlast any particular mattress.