Making an architects plan chest, how can I strengthen the drawer?

[Eif]

I am going to make a large plan chest from plywood, I am just working out how to make the drawers. As the width would be roughly 1000mm and depth 700mm to accomodate A1 paper. Does anyone know how a drawer this wide would usually be strengthened to prevent the bottom of the drawer from buckling?

I was thinking of using a muntin however, I would need the inside bottom of the drawer to be completely flat, so as not to buckle the paper that would sit inside, any help would be greatly appreciated.

 

[peter-harrison]

You could just reinforce the bottom underneath with a bit of hardwood glued in?
Or use thicker ply for the drawer bottom.
I took apart a whole load of map drawers from the Royal Geographical Society many years ago. They were made with 3/8" birch ply bottoms.
By the way, I think your concern may be misplaced. The force exerted by a maybe 50mm high stack of paper won't be that much per square inch, and will be evenly distributed, and will therefore not have a tendency to twist the drawers. I would happily make drawers like that with 6mm ply bottoms.

 

[ChaiLatte]

Over the 1000mm dimension, make the bottom slightly arched. It will not harm the paper but will contribute to the strength. You could similarly make your munchkin slighly arched, as well as choosing the plywood direction so its strongest direction is across the longer span. You could take inspiration from how acoustic guitars are built and braced.

 

[Jacob]

Give it extra support with a central runner under it. Tongued or housed into the front rail with glue and screws. Supported at the back, various ways.
Or just stiffen from underneath with a glued on strip in place of muntin, as per peter's suggestion above. And I agree, probably not that necessary.

 

[Ollie78]

I say make it with a central rib running front to back, I have an old linen press with drawers done like this. Maybe 1200mm wide, 600mm deep.
The "rib" is about 50mm wide by 12mm thick, the panels are beveled to slot in the tongue, it is dovetailed to the front and back.

 

[mwinfrance]

I had one done the way ChaiLatte suggests..worked a treat drawings and water colour paintings in my case , laid flat when taken out.

The "arch" doesn't need to be more than a couple of centimetres in the middle where the reinforcement effectively is running under ( and supporting) the base of the drawer.

 

[recipio]

Something like 12 mm plywood glued into dadoes in the front, sides and back would work very well. It would probably be worth investing in full extension drawer runners although I dislike them in fine furniture.

 

[mwinfrance]

I was taking the "glued in on all sides" as read. But arch each drawer as above as well.

BTW..if water colours are to be stored in it and "fine art" type drawings, pastels etc you'll have to find a way to isolate the artwork from any acids present in the any of the wood used for the plan chest, carcass and drawers.