Here’s the situation:
I have a customer that wants to mount bookshelf cabinets inside a closet. The problem is that they want to keep the existing shelving and make the bookshelves act as doors.
The book shelves are to be 36″ wide x 14″ deep x 80″ tall. There will be two per closet and they will swing open from the center of the two cases. Some quick math says that when fully populated with books they could exceed 300lbs each.
My first thought was to use butt hinges and then ball casters on the bottom but when I stood on a test platform and tried to move it accross a carpet it required an unacceptable amount of force. The customer has now decided to replace the carpet with a high end hardwood floor and I’m now afraid that repetative rolling of castor would most certainly damage the floor finish.
I’m now leaning towards heavy duty ball bearing gate hinges and then reinforcing the back panel with diagonal struts to keep the cases square under weight but allow them to float like a normal door. Having hung a few gates in my life I’m having doubts about this solution and I’m hoping someone here has done this before and has a proven solution.
Thanks in advance…
Replies
It looks like you might get 6 shelves here. That's 18 linear feet of shelving. That sounds like lots more than 300 lbs. Since the weight will be all on the pivot point, you'll have a very large load there and I'd worry about that.
Could some of the weight be handled by somehow suspending the bookcase from above, so that weight is transferred from a single spot to that spot plus the upper supports? By suspending I'm not implying no weight carried by the bottom pivot point, but having the support structure take some of the load off.
John
John, you are correct it will likely be more than 300lbs. More like 500 depending on the books and decorative items. I cant think of any way to support it from above because it needs to swing fully open.
I found that I can get gate hinges rated for the load so I think I've solved that problem. I'm now thinking of setting a 3/4" back panel into a dado about an inch inset from the back then using corner bracing.
If I could figure out how to support it from the top that would sure help but I just can't see anyway to do it.
Thanks for the input!
The hinges will need to be fixed to something rigid and my worry would be a 500 to 800 lb loading on what would probably be a vew square inches. Doesn't sound very good to me.
If the hinges were fixed to a rigid "thingy" (solid oak, some sort of metal, what have you) which rested on the floor but which was also supported and hung from the top, the weight could be spread out. You could bolt a 4X4 oak beam at the top and spread the load, for example. I could even envision the entire load being handled from above, which would allow more cleaning on the floor, but I'd worry about stability (since the shelf structure would swing 90 degrees and the weight stresses would vary).
John
In Jim Tolpin's book, "Built-in Furniture" (Taunton Idea Book), there's a short blurb and a couple of photos of swinging-door bookcases similar to the ones you describe. They're a bit shorter and wider, so I think the weight issues are about the same.
Anyway, the description, although brief, should give you some helpful details. I don't have a copy at hand, so I can't give you the page numbers... but a short sneak peek at your local Home Depot bookshelf or public library should do the trick.
David
"The world that was not made is not won by what is done" -- Mundaka Upanishad
Thanks David I'll check it out.
Over lunch I was thinking about this some more and then wondered why the shelves are 14" deep. That sounds way, way too deep for most books. And if the books are that deep, they're going to very, very heavy. I'd propose a 10 to 12" deep shelf. Since this is a closet it may make things easier all the way around as a side benefit.
John
John, the depth I have to work with is 14". The shelves will be around 12" after the inset back and the face frames are on.
Have you considered pivoting from the center of the case rather than the side? If you have 2 three foot wide cases adjacent to each other and you pivot both from the center rather than the sides, you will still end up with an opening approaching 2'-6" and better distribution of weight and bearing tensions. You could then use a standard center pivot door hardware set. Might work.
No One,
Yeah, cool idea, trim it right and your customer has a secret closet.
After a bunch of ideas I bet you will have few options here. This is certainly a design and building challenge, sounds neat. I would think door hinges. Depending on the weight of a door, interior doors 2 or 3 hinges, exterior doors 3 or 4 hinges. Here your looking at 4 to 6 hinges. The structure they attach to is going to have to be a beast, 2x8, 2x10, 2x12 rectangle. Clad it in solid wood where needed, fixed shelves for the extra structure they would provide and a 3/4" plywood back rabbited in tight, or set in like you suggested.
Do I hear 2 cents, 1 1/2, 1!
Enjoy, Roy
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