Solid wood drawer bottoms

DaveO · 04-29-2006, 11:46 PM

In my on-going saga of my sofa table, I would like to use a solid wood bottom in my drawer. Mainly because I don't want to buy some WO ply to do it with. I have milled, and glued 2 pieces of 1/2" QSWO to the width & length of the drawer bottom (11" x 20 3/4"). I plan to cut a rabbet forming a tongue on three sides to fit into a groove in the sides and front.
My question is should I attach the bottom to the back with elongated holes and screws to allow for movement or just capture the whole piece in a generous groove like a frame and panel. I have read of people just nailing the bottom to the back, but I am afraid that wouldn't allow it to swell and contract.
Thanks for any advice you can offer.
Dave

NCPete · 04-29-2006, 11:50 PM

Dave, it seems that I recall some-one having written about attaching near the front, and leaving the back floating.

BTW, you really should try Sam's Hefeweizen. MMMMMMMMMM Good! Hadn't seen it before.

Monty · 04-30-2006, 12:25 AM

If you're worried about it sagging or rattling, cut a notch in the back of the botom panel (saw kerf), right in the middle, and drive a screw from below into the back piece.

DaveO · 04-30-2006, 12:34 AM

Originally Posted by insomniac

If you're worried about it sagging or rattling, cut a notch in the back of the botom panel (saw kerf), right in the middle, and drive a screw from below into the back piece.

Is that like a elongated hole to allow for movement????
Dave

Monty · 04-30-2006, 12:37 AM

Yea, just an easy way to make the hole.

DaveO · 04-30-2006, 12:39 AM

Originally Posted by insomniac

Yea, just an easy way to make the hole.

Thanks

Dave

4yanks · 04-30-2006, 08:29 AM

I have usually made my drawer bottoms with unglued half lap joints slid them into grooves along the drawer sides and into a similiar groove in the front. I use shims (paper, etc...) to leave about 1/32 between each board. My backs sit just above the grooves in the side. I simply nail the last board of the bottom into the back. The loose nature of the lap joints allows for expansion and contraction. In the case of a solid bottom I would use a screw and a slotted hole (with slotted counter-bore) into the back of the drawer.

Big Mike · 04-30-2006, 10:03 AM

Traditionally, solid wood bottoms were pinned at the front and allowed to expand out the back. The back of the drawer carcass was cut only to the top of the drawer bottom groove so the bottom could contract and expand out the back of the drawer as necessary. Of course this means the grain of the boards used for the drawer bottom must run side to side. The groove in the drawer sides was cut a hair oversize so as to not restrict contraction and expansion.

DaveO · 04-30-2006, 10:35 AM

Originally Posted by Big Mike

Traditionally, solid wood bottoms were pinned at the front and allowed to expand out the back. The back of the drawer carcass was cut only to the top of the drawer bottom groove so the bottom could contract and expand out the back of the drawer as necessary. Of course this means the grain of the boards used for the drawer bottom must run side to side. The groove in the drawer sides was cut a hair oversize so as to not restrict contraction and expansion.

Thanks Mike, that makes perfect sense. A dab of glue at the center of the bottom in the groove in the front should keep it from moving while allowing it to expand out the back. Plus that will help me keep with my no metal (so far) theme. Thanks for the solid (bottom) advice

Dave

Howard Acheson · 04-30-2006, 11:39 AM

Dave, when using solid wood drawer bottoms, the rule is to have the grain running acoss the drawer, not front to back. With the grain running across, there is no expansion to force the sides of the drawers apart which would cause the drawers to bind in humid conditions. You still have to use a construction technique that allows front to back expansion/contraction. For a range of relative humidity annual change from 40% to 75%, you can expect about an 1/8th inch of seasonal expansion/contraction.

Having the long grain run across the shorter dimension will also give you a stronger and less likely to sag drawer bottom.

jeff... · 04-30-2006, 12:26 PM

Having worked on several antiques with solid wood drawer bottoms, I can tell you how I've seen them constructed.

The front and sides of the drawer were normally slotted like 5/8" the back was not. The solid bottoms were usually a 1/2 doweled glue up panel. The drawer bottoms were "pinned" to the back bottom of the drawer with nails or flat head wood screws not tightened in an elongated hole. So basically the drawer bottom floats, in the drawer frame, I guess to allow for expansion and contraction so the drawer won't bind, split or crack in the case during humid weather.

I'm thinking and (I know that’s dangerous), but back then there were no such things as air conditioners so humidity control was non existent. The wood in those pieces of furniture needed to be able to move (expand and contract) freely so they wouldn’t crack or split. We solid wood furniture builders do this same thing today, but we don’t need to go to the same extreme they needed to back then. Thank God, we have air conditioners in this day and age.

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