Drawer Bottom Thickness ??

[Larry Frank]

I am making some large drawers which are 30" x 16". The sides are ash with through dovetail corners and I am using full extension drawer sides.

I am trying to decide what to do about the bottoms. I think that 1/4" ply even baltic birch will be too thin. I am thinking of using 1/2" baltic birch. Instead of cutting a 1/2" groove on the inside of the drawers for the bottom, I was thinking of cutting a 1/4" groove and rabbeting the 1/2" plywoom to 1/4". Does this sound OK?

[Joe Scharle]

Onfile:///C:/Users/COMPAQ%7E1/AppData/Local/Temp/moz-screenshot.png wider drawers I use a center divider/runner. Drawer bottoms are 1/4" and are dado'd into the runner as well as the sides. The runner is in contact with the middle stile of the web frame to support the weight.

file:///C:/Users/COMPAQ%7E1/AppData/Local/Temp/moz-screenshot-1.pnghttp://www.ncwoodworker.net/pp/data/632/Child_s_Dresser_005.jpg

[John Keeton]

I would use 1/4", and do as Joe has done, though I am not sure you absolutely have to have support under the middle divider if it is supported front and back in the drawer. Depends somewhat on anticipated loads. If it is for clothing, I wouldn't be concerned. Fill it with metal tools - whole different story!!

[glenn bradley]

+1 on Joe's method depending on weight expected.

[Richard M. Wolfe]

Supporting the load in the middle sounds good. Unless the drawer bottom was in complete contact with the sides, rabbeting to 1/4" would result in only 1/4" support.

[Larry Fox]

I have some drawers like that in my kitchen - I used 1/2". They hold pots and canned goods. 0 sagging. Why take the chance.

[Richard Gillespie]

Use to work in cabinet/furniture shop. Drawers were made with 3/8" plywood bottoms using full 3/8" rabbits. They hot glued the parameters of the drawer bottoms after squaring the drawer. Center supports were not used. The company advertised the strength of it's drawers by having a 140 pound supervisor photographed sitting in them. Food for thought.

[Charlie Plesums]

A 30 x 16 drawer sounds like a bedroom drawer. No problem using 1/4 inch plywood without supports. I often use even thinner 5.2 mm plywood sold as moisture resistant underlay at the BORGs - no voids and one side is pretty nice.

For kitchens with pans and cans, or entertainment centers with a ton of CDs, you do need a heavier bottom.

[Tom Cross]

I am redoing our kitchen. Drawers are up to 30" x 21". I am using 3/8" baltic birch plywood, no sagging at all, 1/4" had some sagging. I would do 3/8", not 1/2". My local lumber yard ordered it for me in 60" x 60" sheets.

[Glen Butler]

30 by 16 is not that big of a drawer and the bottom is only spanning 16" not 30". 1/4" will be fine unless you are really loading up that drawer. Beyond that a center support will do the job, and beyond that the drawer glides will fail first.

[Alan Tolchinsky]

Use to work in cabinet/furniture shop. Drawers were made with 3/8" plywood bottoms using full 3/8" rabbits. They hot glued the parameters of the drawer bottoms after squaring the drawer. Center supports were not used. The company advertised the strength of it's drawers by having a 140 pound supervisor photographed sitting in them. Food for thought.

Doesn't just rabbeting the drawers reduce the strength? I thought that dadoing was better to support the weight. With rabbeting, what really keeps the drawer bottom from falling out the bottom besides the glue?

[John Morrison60]

I have made a lot of drawers, kitchen, utility, bedroom, and shop.

On some very large shop drawers, holding routers and routing stuff, I used 3/8 B.B.
On all the rest, including some pantry drawers that hold a lot of weight,
I have standardized on 1/4 inch baltic birch.
If I have wanted to stiffen the drawers (did this on pantry drawers)
I simply glue anther thickness of 1/4 B.B. onto the bottom of the bottoms.
This stiffener doesn't go all the way to the sides (depends on the sizes in my offcut pile), and does not interfere with the drawer glides.
This method really stiffens the drawer and is also a way to add a stiffener after the drawer is assembled.
It is stiffer than the 3/8 thick plywood, and is a great use for scrap pieces of plywood.

John

[Frank Drew]

If I have wanted to stiffen the drawers (did this on pantry drawers)
I simply glue anther thickness of 1/4 B.B. onto the bottom of the bottoms.
This stiffener doesn't go all the way to the sides (depends on the sizes in my offcut pile), and does not interfere with the drawer glides.
This method really stiffens the drawer and is also a way to add a stiffener after the drawer is assembled.
It is stiffer than the 3/8 thick plywood, and is a great use for scrap pieces of plywood.



Sag resistance (stiffness) of a piece of plywood is largely a function of material and glue lines, so John's method adds glue lines to a piece of 1/4" material, thus increasing bending resistance. Larry's orginal question about rabbeting a piece of 1/2" ply is, basically, the same thing -- it's going to be stronger than a piece of 1/4" material even though the tongue is only 1/4" thick.

Aesthetically and structurally, I like the center divider design.

[Richard Gillespie]

Doesn't just rabbeting the drawers reduce the strength? I thought that dadoing was better to support the weight. With rabbeting, what really keeps the drawer bottom from falling out the bottom besides the glue?

My mistake, sorry, the drawer sides were 9/16" thick sycamore dado-ed, not rabbited, for the 3/8" plywood.

[Alan Tolchinsky]

Thanks for clearing that up Richard. I just wanted to make sure I wasn't misunderstanding what you were saying.

[Brian Peters]

small drawers 1/4" and large span drawers 1/2".. I wouldn't rabbet the plywood unless you had to - I would dado it in a full 1/2". If you are doing 1/2" dovetails sometimes it will cut through and you just have to make plugs. Pin nail and hold melt glue the bottom after assembly esp. on the large ones so there is no rattle.