Dado for drawer bottom

[trampis]

Greetings all!

I don't remember if I've posted or not it's been so long since I've been on this forum but here goes...

I'm building a large slide out drawer for the bottom of an outdoor BBQ cabinet. It's going to have a couple of propane tanks on it and some other supplies.

The dimensions for the drawer are 29"d x 36"w x 5"h.

I'm planning on having dados on the sides to support the bottom. My question to you all is do you think 1/2" plywood is strong enough for the bottom or do I need to go to 3/4" considering thw size of the drawer? I'll be using Baltic birch. And would 1/2" be thick enough for the sides?

Thanks in advance!

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[ChuckM]

"It's going to have a couple of propane tanks on it and some other supplies."

Are you placing the tanks on the drawer? If so, I'd use 3/4" stock. Or a cross bar to support the bottom.

 

[trampis]

"It's going to have a couple of propane tanks on it and some other supplies."

Are you placing the tanks on the drawer? If so, I'd use 3/4" stock. Or a cross bar to support the bottom.

Yes, they'll be on the drawer although they're not the heavy steel 20lb tanks. These are lighter weight.

Do you think dados in the 1/2 ply will suffice or do I need to make the sides out of 3/4 to give the dados more depth?

Thanks for the reply!

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[ChuckM]

Unless the tanks have little weight, I'd use 3/4" stock for the 4 sides and reinforce the 1/2" bottom with a cross member to avoid sagging.

 

[tjbnwi]

Use under mount slides, they will support the drawer bottom. The drawer will need to be 27” or 30” deep. The relief off the bottom of the slide is 1/2”

You’ll need to put a center stiffener on the bottom of the drawer deck.

Tom

 

[trampis]

Thanks guys, I will do more planning accordingly [emoji1688]

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[Steve1]

For comparison, these drawers on my workbench are 38" wide, with 3/4" sides and 1/2" bottom.

I would have no concerns putting 50 or more pounds in it.  I wouldn't go thinner than 3/4" for sides, and don't really see a need for going heavier than 1/2" for the bottom. 

If you are using Baltic Birch, yours will be much stronger than mine.    I saw a good price on alder plywood so gave it a try.  Horrible stuff.  Can't hardly sand the edges without breaking off splinters.

If you are using drawer slides, you can find 3/4" wide heavy duty slides (standard is 1/2" thick), but I don't know how they will survive outdoors.

 

[Packard]

[…]The dimensions for the drawer are 29"d x 36"w x 5"h. […]

About 35 years ago, I built a cabinet for holding “Art” in prep for framing.  The drawers had to accommodate the largest standard size mat board which is 32” x 40”.

Working from memory now, the drawer sizes ended up being 44” wide by 36” deep.

I had a minimal amount of weight, so that was not an issue.

The sides bowing outward was.  They could not bow inward as they would hit the drawer bottom.  But they could bow outward and leave the middle of the drawer unsupported by the dadoes.

I got my inspiration from a book published in the early 1970s, but probably from an even older transcript.

This is the drawing I based my drawer on:

They show the drawer bottom as two pieces.  I did not do that.  I did add the cross stringer beneath the drawer bottom.  I did use the dovetail joint as the isssue I was facing was bowing outwards, and the dovetail works perfectly for that.

This was the very first dovetail I ever made and it was surprisingly easy.  I drew and cut the stringer using a back saw.  I then traced the dovetails onto the drawer sides and cut the dovetails until the dado groove.  I don’t remember how I cut the dovetails out of the sides, but probably with a coping saw. 

I then glued it in place.  It worked perfectly for limiting the bowing.  I cannot report on the support it provides underneath as the art weighed in, in ounces not pounds. 

And here is a sketch showing the approximate dimensions I would use for your sized drawers and your weight holding requirements.  Basically, seat-of-the-pants-engineering.

The sketch at the top of the page shows the drawer sides.

The sketch at the bottom of the page, shows the stringer for the bottom.  The overall length needs to match the outside dimensions of your drawers.  The dovetail ends need to fit cutouts on the bottom of the drawer sides.  I think your dado’s distance from the bottom should be 3/4”, and the depth of the dado should be 3/8”.

The drawing from the book shows stopped dovetails.  I cut the dovetails on the drawer sides all the way through. It made a very easy job.

I did not have enough clamps for the drawers (there were about 10 drawers).  As I recall, I used very small (#6??) screws to hold the dovetail in place as it dried.  I probably used 3/4” x 2-1/2” poplar for the stringer. 

I was very impressed with myself when I discovered that everything worked as planned.  Though the cabinet, built in 2 modules, was extraordinarily heavy and difficult for even two people to carry out of my basement.

 

[trampis]

Thanks for all the replies gang! I'm going to go with 3/4" on the sides and 1/2" for the bottom. I've purchased some full extension HD slides with locks so we'll see how the project goes. I'm pretty sure it'll hold up the propane tanks as these tanks are composite and weigh significantly less than the metal ones.

Love this forum and look forward to many more interactions in the future!  [thanks]

 

[Packard]

If you are using plywood for the sides and the bottoms, you can glue the bottom into the dado as seasonal movement will not be an issue.  That will allay any worries about the sides bowing out and the bottom becoming loose.