# drawer bottom thickness & do you rabbit thicker bottoms



## JesseTutt (Aug 15, 2012)

I am working on more drawers for workshop storage. The current set is 16" wide x 22" deep x 12" high and made of 3/4" plywood (it's what I had on the rack). A couple of drawers will be holding close to 100 pounds each. Instead of using 1/4" ply, should I switch to 1/2"? If so, do you suggest that I cut a 1/2" grove in the sides or 1/4" and rabbit the bottom?


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## nwbusa (Feb 21, 2012)

Yes to 1/2" ply. Yes to a 1/2" groove (dado) as opposed to a rabbet joint. You'll lose a bit of drawer space but it will be stronger.


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## wapakfred (Jul 29, 2011)

Another vote for the 1/2"...but I'm thinking (if I understand it correctly) the choice between that 1/2" groove or a 1/4" groove isn't really that big a consideration (the 1/4" rabbet would have just about the same strength I think). But it would be easier to just make a 1/2" groove. Is there a reason to not do it that way? BTW, skip that floating panel/bottom concept…glue those suckers in!


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## MJCD (Nov 28, 2011)

Absolutely dado the 1/2". Since it's all plywood, you can glue all joined edges


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## kizerpea (Dec 2, 2011)

100LBS? in one drawer…need to find somewhere else to store the fishing lead…


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## LeeBarker (Aug 6, 2010)

Another option to consider: 1/4" tempered hardboard ("masonite"). It won't break.

Actually I think 1/4 fir plywood would be fine as well, glued in. I would avoid mdf-core 5.2mm material.

1/2" material seems overkill to me.

Once you get all the gold ingots in there, the drawers will be fine so long as you don't use them as a pullout stepstool.

Kindly,

Lee


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## Domer (Mar 8, 2009)

Stickley website shows people standing in their drawers and they use 1/4 in plywood.

I made a kitchen island that has pretty large drawers and it is full of dishes. I have never weighed them but they are pretty heavy and have not had any problems.

Make sure your slides are adequate to hold the weight.

Domer


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## MrRon (Jul 9, 2009)

My vote is for a 1/4" rabbit and 1/2" plywood.


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## bondogaposis (Dec 18, 2011)

I also vote for some kind of rabbet joint and dado because as we all know 1/2" plywood is not actually 1/2".


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## Gene01 (Jan 5, 2009)

I'm an overkill kinda guy I guess. I would use 1/2" ply on a drawer of that size an the weight you have.


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## AlaskaGuy (Jan 29, 2012)

post deleted


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## teejk (Jan 19, 2011)

100 lbs is a lot! I'd opt for dado over rabbet. weight will be on the drawer box as opposed to relying on glue/nails.

with that weight you only want to do it once otherwise you have to pull it all out and start over. 16"x22" will certainly "test" 1/4" anything even at half that load so I'd opt for 1/2" (I'd even think about 3/4" but then think about a snow load on a roof where 1/2 seems to be ok).


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## nwbusa (Feb 21, 2012)

I've made drawers that are 46" x 28", one of them 15" deep and *loaded* with well over 100 pounds. 1/2" Baltic birch plywood bottom dadoed into the 3/4" BB drawer carcass was plenty sufficient.


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## AlaskaGuy (Jan 29, 2012)

I have built a lot of drawer over the years. When I make all plywood drawers I use 1/2" Baltic Birch sides and 1/4 Baltic Birch bottoms set in a 1/4 dado. The 1/4 Baltic Birch is dam near a full 1/4 and fits in the 1/4 dado perfect. Its pretty darn strong too. All my shop drawer, kitchen drawer are made this way. At my work place with the School District I've built a lot drawers with 1/4 bottoms for years. No problems.

I the picture below my wife who weight in at 120 lbs is standing smack in the middle of a 22 X 44'' drawer that has a 1/4'' BB bottom. I measured the deflection in the middle and it was 1/4''. I generally use 100lbs rated full extension ball bearing side mount drawer slide which I figure will fail before the drawer bottom will. If you like to over build I'd say you're well on your way.

BTW what you using for drawer slides?


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## JesseTutt (Aug 15, 2012)

Thanks!

It sounds like we are about evenly split.

Last night I went ahead and used the 1/2" (slightly less) for the bottoms. It may be over-engineering but I will feel safest, also it allowed me to use up some 1/2" scrap.

For drawer slides, I use the 75 lbs white epoxy slides for smaller (and lighter) drawers and 100 lbs Centerline (Rockler) for the large (and heavy) drawers.


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## Gene01 (Jan 5, 2009)

Good choices, Jesse.


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## LeeBarker (Aug 6, 2010)

What's missing in this discussion is a clear understanding of what would happen when a drawer failed because of too much weight inside it.

AlaskaGuy's test for deflection is valid for that number.

However, I submit that if you took a drawer and put it up off the floor with supports that were only under the sides, you'd be mimicking the drawer as suspended in the carcase via the slides. Now start adding weight.

Which will fail first, the bottom itself or the rabbet that's holding it in the sides and front?

On another note, AlaskaGuy wisely noted 100lbs rated drawer slide. I have been told by product reps that the "rating" is based on the shortest slide in the family. It is reasonable to assume that 100lbs. in a drawer that extends 12 inches will have a different effect on the hardware than 100lbs. in a drawer that extends 22 inches.

Kindly,

Lee


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## joeyinsouthaustin (Sep 22, 2012)

If you leave 1/2" or 3/4" under your rabbit for the bottom, you can install a 1/2" x 3" or 3/4" x 3" stretcher underneath the bottom, from the front to back of the drawer, centered side to side. One dab of glue in the center and then the drawer bottom can still expand and contract, glue and pin to front and back.

Benefits: It will also keep the front and back from bowing, and will re-enforce the bottom with less material.. better yield. We do this in all our 1/2" baltic birch drawer boxes with only 1/4" bottoms and 1/2" stretchers. I have had heavy duty blum guides fail before the d box does.


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## TerryFerguson (Feb 5, 2011)

You have gotten good advice from all above and I would agree with either approach. At this time, you have already gone ahead with your decision and there should be no problems. 
FYI. another thought: 
I use 1/4" ply or lumber bottoms in my shop drawers (no metal slides) fit into 1/4" grooves and I always install one or more partitions that run side to side or front to back or both. The partitions will give the bottom more support while giving the drawer more organizational possibilities.


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## DS (Oct 10, 2011)

If I a had a nickel for every drawer (of someone else's) I had to replace made with 1/4" bottoms where it deflected only 1/4" and stayed that way, permanently, until it fell out altogether…. oh, wait… I got paid a *lot more* than a nickel to replace those with drawers made with 1/2" ply bottoms!

Anytime I expect significant weight in a drawer, I *always *use thicker ply for the bottoms.
That was a good call.

The difference in cost is insignificant compared to the cost of a failure.
I still run 1/4" ply bottoms on standard drawers. though.

Haven't used PB, or MDF in a drawer in many, many years-BB Ply and/or solid wood is it for me.


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## AlaskaGuy (Jan 29, 2012)

DS251

My day job is in the carpentry shop of out local School District. We have 90 some odd school and 15 support buildings. We must have 100,000 drawers maybe more I never counted them all. One of my duty is fixing broken drawers. We have all kind and sizes of drawer made out many different material and most of them have 1/4'' bottoms. If I had 10 buck for ever drawer bottom I have to repair I'd starve to death. If fact I can't not remember (over the last 15 years) a single drawer bottom that failed it self. Usually a corner comes apart or some other damage before the drawer bottom fails.

Can't explain why your experience is so different than mine. In my example of concentrating 120 lb load in the center of the drawer is not a real life example of how drawer are used. In real life the load will distributed much more evenly through out the drawer bottom and you would get near that much defection.


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## DS (Oct 10, 2011)

AlaskaGuy,

I think we've had a similar conversation on a different thread. I basically agree with you.

Sorry, if my post makes it sound like all I do is replace drawers-I don't. I've been at this biz since 1986 and have seen my share of drawers of every type, style and size.

FWIW;


I've *NEVER *had to replace any of *my own *drawers.


In the Metro Phoenix area throughout the 80's and into the 90's many builders were using el-cheap-o cabinets with particle board, and/or melamine drawers and 1/4" MDF, or HDF bottoms. They had no objection to this construction even on larger and more heavy duty use drawers. Many of my builder clients bring these old broken drawers to me to repair for them since the original manufacturer is no longer around. (no big surprise there.)


I believe I stated that my standard drawer uses 1/4" BB ply bottoms. It's a terrific material for drawers, to be sure. Just like yourself, I've never had a problem with this.


I automatically upgrade the bottoms to 1/2" BB ply whenever heavy duty, or large drawers are involved, just to err on the side of caution and to avoid a situation from EVER occuring where my product might appear to be flawed, sub-standard, or cheap. (I prefer to leave that imagery in the 80's where it was deserved.)

Is it overkill?

Probably. But then again, I can sell on the basis of quality with absolutely no regrets.


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## pmayer (Jan 3, 2010)

I am building a pair of dressers right not and I couldn't decide between 1/2" and 1/4" drawer bottoms so I went with 3/8". I use 1/2" for heavy duty drawers, but I think good quality 1/4" BB ply is plenty for most applications.


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## Wdwerker (Apr 14, 2012)

For oversize drawers or drawers meant for heavy loads I use 1/2 ply rabbeted in a 1/4 groove with 3/4 of ply below the groove. The weakest part of the drawer is the amount of support under the groove. The reason to use the 1/2 ply bottom is to reduce deflection, just need to keep the bottom stiff. I recently built pantry drawers 36"w x 23" deep with 7" h sides of 5/8 Baltic birch. Used 150 lb rated lateral file slides and 1/2 Baltic rabbeted for the bottom. Pulled the drawer all the way out and climbed my 200+ butt in to show the client how sturdy the drawers were. Immediately warned him not to do this with a snoot full at his next party< grin >

Craftsmanship+ quality materials+ouality hardware= long service life!


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## nwbusa (Feb 21, 2012)

Even though I use 1/2" BB bottoms, I admit it's probably overbuilding. If you are taking reasonable care of your drawers (i.e. not dropping cannon balls into them from over your head) then 1/4" BB (or other quality ply) will probably be sufficient.


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## pmayer (Jan 3, 2010)

Wdwerker makes a great point about the amount of material below the groove. That is critical for heavy loads, and I extend this for larger drawers as well to about 5/8" to 3/4" as well.


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## LeeBarker (Aug 6, 2010)

Once again we have decisively proven that your mileage may vary. Hooray for LJ.

If someone is keeping score:

In 31 years I've never seen a drawer that has a failed bottom. The failure is always something connected to the drawer face. This experience includes the wretchedly cheap factory units as well as stuff of reasonable custom shop quality.

To say that adding a 1/2" drawer bottom just to be sure there is no failure is a specious argument. You'll have to then convince us why you don't go to 3/4 or 15/16 material for the sides…and on and on. And to put something thicker than 5.2mm in a dresser? Perhaps there's always the possibility it will be used to hold a priceless collection of anvils.

When we say we always put in 1/2" material and never had one fail, are we saying that by folding paper twice before putting it in the recycling we are keeping the peacocks from nesting in the attic?

I suspect that shop drawers owned by you are about as burdened as any. Perhaps they're not treated as roughly as a knuckle-dragging employee might, but still we're talking about load here, period. I'm interested in hearing the story of a shop drawer with a quarter inch bottom, glued, dadoed four sides, that failed because of the load. And I'd like to know what it looked like after the failure.

Kindly,

Lee


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## teejk (Jan 19, 2011)

I hear you Lee…if the drawer box itself doesn't fail, the bottom has little place to go on a 4 side dado box even though it might want to. but the other benefit of 1/2" bottoms is one can sink some brads as insurance…hard to do in 1/4 material.


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## DS (Oct 10, 2011)

Lee, the classic example is the pots and pans drawer below a double oven. This is usually about 30" wide and about 22" deep. (YMMV)

Granted, the ones that have given me most issue are the 1/4" HDF (Masonite) bottoms. While they initially are very sturdy, many years of significant weight and the ocassional pot put away wet is not such a friendly environment for HDF. Even elevated relative humidty levels can weaken HDF, when under a constant weight load. Cold rolled melamine isn't much better, as it has minimal water resistance and once water penetrates the laminate layer, it has little remaining strength.

The center of the drawer sags and begins to resemble a shallow dish. This shape is retained even with all the items removed from the drawer. Over time, this continues until it sags far enough to impede proper drawer function. At that point, mechanical stresses mount and the drawer quickly becomes toast.

By far the most common drawer failure is at the box corners and usually due to abuse. Certain drawer guides are not well equipped to take the dynamic load of a weighted drawer closing. (No positive stop) The Blum 230M was the worst for this, even though it is likely one of the most prolific guides ever sold. The drawer front took the brunt of the closure force and this stressed the joints dramatically when closed with any force.

Dovetail jointed plywood, or solid wood boxes helps strengthen it against this issue, but a good positive-stop guide also prevents the issue before it can start.

Even if 1/4" plywood can stand the test of a heavy load, ocassional moisture and abuse, the sight of it sagging, even a little, when the stew pot is laid inside gives the impression to the end user that maybe it isn't as sturdy as it ought to be.

Again, I try to err on the side of quality.


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