Assembling a custom built-in for our living room with an extra wide drawer (53″w x 22″d). The issue I’m dealing with is how I make sure that I am properly supporting the drawer over the 53″ span, both structurally and in terms of the slides. I can’t find much about extra wide drawer building online, hoping someone here has some thoughts.
To provide some context, the base cabinets will be 24″d x 27″ high, 3/4″ ply (backs, sides, bottoms, with 2-3″ 3/4″ ply strips for box tops and top front). It will have 3/4 face frames (painted poplar or similar) and a 6/4 hardwood top that extends across the three cabinets. The middle cabinet will be 54.5″ wide, and the whole thing will rest on a 2×4 ladder, and there will eventually be a bookcase on top (also made with 6/4 hardwood).
Returning to the drawer, it’s for a digital piano, which is about 6.25″ h x 11.5″d x 51″ w and 26.5 lbs. It will have a fold down front and slide out (drawer), kind of like a very wide computer keyboard tray. The keyboard will be in the front portion (with an open front edge), there will then be a cross brace in the middle (behind the keyboard, “inside” the drawer), a second space for music books, and then the back wall of the drawer. Think of it like a partitioned drawer (front/back) with an open front edge.
My plan is to build the drawer sides/back/partition from 1/2″ hardwood, the bottom from 1/2 hardwood ply, and to put two 2-3″ braces front to back in the drawer underside. Assembly will be dados + titebond + brads. I estimate the total weight of the drawer + contents will be 40-50lbs. Specific questions as follow:
1) Given the lateral cross-brace (front/back partition) and the 2 underside braces, is the 1/2″ material sufficient for the weight/span? Or do I need to bump up at least the sides/back to 3/4? I don’t think it’ll sag, but maybe I’m wrong?
2) What kind of slides should I consider? I’d like to put undermounted slides on (Blum), but they seem to generally have lower weight ratings than side mounted. They still double my expected load, but is that enough?
3) All of the slides I’ve looked at include max width drawer ratings, and most don’t exceed 40″ or so. Is there a reason? Assuming the drawer is solid and the slides meet the weight, is there another problem I’m not seeing with a 53″ drawer? Is because of potential racking on the drawer?
Thanks in advance for any insights, much appreciated.
Rick
Replies
For a span like that I would choose baltic birch plywood. Very stable and solid plus the edges sand almost to a polish. Consider upping the corner joinery to locking dados.
For the hardware you'll want it to lock in the open position to play the keyboard... not sure that's available in a deep undermount slide, it may be that computer keyboard slides are the way to go if they come deep enough. I have used ball bearing slides laying on the flat under pullout shelves, something like that could eliminate the sagging concern.
Good idea, but I really don't want any ply sides showing, even if they're nicely finished. This is in my living room, so I plan to use solid wood for the drawer frames, which I would think would be more laterally stable than the same dimension ply. The bottom will be 1/2" birch ply though. Make sense?
On the drawer, yeah, locking would be ideal, but I haven't been able to find anything that can handle the span/weight AND locking. Current plan is to build some kind of custom block locking system, maybe with pivoting 1/2" inside the rear drawer partition (you open the drawer and spin the blocks "up" to lock the drawer in place).
-rt
How heavy is keyboard?
3/4 sides and bottom. Laminating bottom will add strength.
Blum tandem heavy duty’s with anti rack cross stabilizer.
UPDATE
Just took a closer look at the Blum lateral stabilizer system. Unfortunately it's rated max 53" (53 7/32" to be precise). Planned inner dimension of my cabinet is 54.75" (56.75" - 2 x 3/4 ply sides). The piano is exactly 52.25". Assuming I leave a min 1/4" of wiggle room inside the drawer puts me at 52.50". Even if I use 1/2" hardwood for the drawer sides that puts me 1/2" over the stabilizers max width.
I might be able to DIY a custom lateral stabilizer bar (which is the issue), but that seems like a real pain, especially since I have no idea how that stabilizer bar secures to the pins on each side (looks like it locks).
Have you used this slide in a cabinet wider than 53"?
ORIGINAL
Piano is 26.5 lbs. Not sure what the unloaded drawer weight will be, but I assume it won't exceed 15-25 lbs, which is how I get to 50 lbs max.
Interesting on the Blum anti-rack stabilizer, hadn't seen that. Looks like a bit of a pain to install with that extra runner though... is that glued to the face? I also found the Accuride 3160 EC, which looks interesting? Not much less complicated with the anti-racking line, but at least it's contained?
https://www.accuride.com/en-us/products/3160ec-soft-close-undermount-slide-for-ultra-wide-drawers
-rt
I made a map cabinet many years ago with drawers that were 60" wide and 48" deep. I used heavy-duty full-extension pantry slides without a problem Never determined the weight of the drawers with contents, but a three-inch stack of large blueprints is pretty heavy. The challenge I found was not the function and durability of the drawer slides, but the rigidity of the drawer. Baltic birch bottoms were my friend. If you could include a sturdy drawer divider in your design, you could mount multiple drawer slides on the flat beneath the pull-out.
Just guessing but the piano would probably only bear on the drawer at its corners. I'd be inclined to make the drawer basically in the NK style but with Blum undermount drawer guides.
Really great insight on the footing. I hadn't even considered that.
The digital piano is largely flat, but it does have round feet (3/8" high x 1" diameter?) that it's supposed to sit on when placed on a surface (we currently have it in a manufacturer piano stand thing where it's edge mounted). There are 4 feet at the corners, inset about 5" or so from the side of the piano.
That being the case, almost all the weight will - I assume - be within 6" of the drawer sides, especially since the drawer will only be slightly wider than the piano itself. So, I don't know the math, but I would assume the potential for flexing/bowing the bottom panel would be pretty low?
-rt
Those slides look like winners. I'm with RobertE on the thicker than 1/2" base.
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