I’m in the process of constructing a bookcase that will wrap around a corner. The 3/4″ oak plywood shelves will meet in the corner, I currently do not have any additional supports planned. There will be a 1.25″ rail on the front of the shelves. See the photo attached.
I’m building this system in the shop and will have to deliver it in pieces. What’s the best way to connect these two plywood pieces?
Getting the details right for a wall assembly with the control layers to the exterior and lots of drying potential.
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Replies
Could you cut each corner shelf from a single piece of plywood, using what's left for the other shelves?
Could you cut each corner shelf from a single piece of plywood, using what's left for the other shelves?
That would work if I didn't have to transport it to the house. Each shelf will be a little over 3'.
That would work if I didn't have to transport it to the house. Each shelf will be a little over 3'.
I must be missing something. Why can't you transport "L" shaped shelves that are 3 feet on a side? Aren't the backs much larger?
All said and done this would be about 3'x4' and fairly heavy. I would have difficulty transporting, lifting moving into the house, etc. Yes, it could be done, I would just prefer not to.
(I would also have to buy more plywood, which doesn't fit into my schedule at the moment)
OK, I gotcha.
3' is a heck of a long span for a 3/4" shelf. It would be fine for pictures and knick kneack but if it's going to be full of books that's another story.
Is 3' the total length or just the front edge where they meet. Joining the peices as shown also requires that you know precisely what the angle is where the walls meet. If it's anything other than 90 the problem will be accentuated quite a bit over 3 ft.
If they are set on having the design as shown I would make a torsion box with 1/4" mdf skins and a 3/4" honeycomb core and veneer the whole thing in oak. Probably overkill but it won't sag and there won't be a joint to contend with.
I guess it depends on the level of fit and finish you are trying to acheive.
Edited 9/6/2007 1:15 pm ET by TomW
There will be a 1.25" front rail on each shelf. There will be a mix of books and knick-knacks on the shelves too - should be fine.
I'm not too worried about the corner of the room. These are going up just like cabinets, full built in floor to ceiling. I'll have shims behind as needed. I'm planning on starting the install from this corner and working left and right after.
How long are the shelves?
You can join the shelves with splines/glue, but they'd be a bear to adjust if these are adjustable shelves. You'd also need support along the back edge if you expect that area to carry some real freight, like books.
On bulky jobs like this, i build each section as a discrete unit, then level like cabinetry on a plinth and trim it out. It takes more ply to have an upright on each side of a section and you'll probably need help hauling the sections in the house, but you can do a lot more assembly, more carefully, in the shop so the in-house time is minimal.
Just for clarification...
The right side of the corner will be a standard shelf unit, with two uprights on each end. The left side will be the tricky one. It will have one upright on the left end and connected to the right unit on the other end.
On the left side, I was thinking about using a piece of 1/2" ply for the back panel and putting some screws through from the backside for extra support. I like the idea of the splines, that should be easy enough.
Your suggested construction technique is exactly like mine. I can get really square/true cabinets in the shop.
<<Just for clarification...The right side of the corner will be a standard shelf unit, with two uprights on each end.>>Clarification? Now it sounds like your description and drawing don't match...i'm confused. If you're using 1/2" ply for the back, rout a recess for the shelf ply instead of relying on just the screws to take the load. If you don't, even with a stiffened front edge, i think you're going to see sag, depending on load, over that 4' span from the left side of the corner unit to the wall. Early on in my career, i tried spanning nearly 4' with 1.5 stiffeners on the front, adj shelving. They sagged. I didn't plan for the worst-case scenario for a professor/lawyer couple. As it turned out, the FLOOR sagged too, and had to be supported better.Any chance you can just exclude the corner? That's what i do if the storage isn't critical. No need to deal with off angles then (except trim, perhaps) and it visually looks better.
You could try pocket screws if you want to be able to disassemble the unit, though you may be able to see some of the screws on the higher shelves. Or you could use biscuits if you want it to be permanent.
I'd pocket screw them.
I'd also dado them in not only on the sides but also into the back, change the backpanel to 1/2" material and go maybe a 1/4" deep.
I'd still be a little worried about sagging if the customer was going to load up all the shelves with book.
Edit: For the pocket scres, Kreg makes plugs that will fill the voids, though I've never used them I know they are available in a variety of wood species as well as black and white plastic.
Have you confirmed the corner in the house is square? Speaking from very recent experience, somtimes you need to tweak a corner cabinet a bit out of square to work.
Edited 9/6/2007 3:07 pm ET by CAGIV
Sounds like a perfect job for a Festool Domino, spacing and size determined by the expected load. Splines would work but the set up time and cutting the slots would be a bear. Splines would not be as strong as the dominos tenons either as most spline stock is cut with the grain. Besides this would let you buy a new tool and vaccum system, a toofer as it were.
JF
<<most spline stock is cut with the grain>>Well, then that's just a bad idea! <G>I make my splines (for indoor use) of baltic birch plywood.
I'd miter them .... and use dowels.
'cause I think dowels are stronger than biscuits. (could be wrong ... but I ain't changing)
and ... I'd build the carcass ... and the shelves ... seperate.
I'm thinking at least this corner is fixed shelves ...
I'd use either 1/4 or 1/2 ply for the back.
I'd use at least 1/2 ply as a spacer/backer ... to lock the shelves in place
carry in the carcass ... set it and install it.
then ... glue / pin the bottom spacer. Goes against the back walls.
let's call it 15" ... if that cab back is 3ft ... it's a 3' by 15" tall piece of 1/2" ply.
both sides ... then set in the shelf.
rests right on the edge of that spacer.
then ... another spacer ... another shelf ... and up we stack.
const adhesive to glue toe spacer to the back ...
yellow glue to glue the shelf to the spacer.
coupla 18's ... Bang ... Done!
and strong.
and my shelves would also have a front rail of some kind.
back can't sag ... front won't.
Jeff
Buck Construction
Artistry In Carpentry
Pittsburgh Pa
Basically you have a 6' shelf with no supports. This design is not strong enough. The shelf you pictured will sag. There should be another support running vertical in the corner.
You get out of life what you put into it......minus taxes.
Marv
Edited 9/6/2007 4:56 pm by Marv
Basically you have a 6' shelf with no supports.
I have to disagree (if that's Ok). The unit on the right side will have uprights on both ends of the shelf. This shelf will be plenty strong enough after I put on the rail.
The left side will have an upright on the left end, splined/biscuited/doweled/festooled to the shelf on the right and screwed or dadoed from the back.
I'd be inclined to use 1/2 inch ply backer and dado the shelves into it, spline the join and then dowel the shelves through the back and front for about half their depth with 1/2 inch dowels, staggered at equal intervals.
Won't be easy, no matter how you do it.
Take some pix when you're done, eh?
Biscuits, or the venerable craig jig.
Another vote for Kreg pocket screws. With oak plugs. I just saw some of the oak plugs at Blowe's last night.
I would use a glued spline joint.
I pretty much agree with Jeff Buck. I've done similar shelves and dowels have worked great. Very strong, invisible, and easy to disassemble (if you don't glue them). If you have to cut the shelves on site, a self-centering doweling jig is easy to use on site too.
I think I would NOT miter the corner. I would use dowels where the end of that shelf butts against the back of the cabinet, and dowels where the adjacent shelf butts against the front edge of the first shelf. That way the support is invisible and very simple to install. If the back panel thickness is too skinny to hold the dowels, you can reinforce only the areas you need by gluing 1/2 inch material on the back side.
That would work if I didn't have to transport it to the house. Each shelf will be a little over 3'.
I must be missing something. Why can't you transport "L" shaped shelves that are 3 feet on a side? Aren't the backs much larger?
I think I misunderstood what smslaw was saying, but it gives rise to a different approach -- why not cut the "L" shaped pieces out of a single piece of plywood and only install them AFTER you've got to the job site? That is, the left and right units can be preassembled, but install the "L" shapes last, and on site.
I know you said you didn't want to buy more plywood, but it still might be a good option for you if you relaxed that constraint.
Edited 9/7/2007 1:07 am ET by Ragnar17
hey ,
Half lap rabbet-3/8 X3/4 , maybe 3/8 X 1/2. Left into right .
With out a design change, 3-0 ft shelves are going to bow under weight.Adding 1X2shelf edging will help, but a stile in the corner is what is really needed.
Design should follow function.
DAVE
http://s182.photobucket.com/albums/x208/dryhter/?action=view¤t=mz_0508_10009669134-1.gif
I am reading all of these options and if the person doing the install is paid by the hour it would work great, ie dados, splines, dowls, pocket screws etc. etc. If however you are paid by the job the domino would take a slow person about 1 minute per joint to build and be as strong as any spline or dowl and much stronger than biscuts. If you have all day to screw around with the project go for the cheap.
JF
and you'll spend a grand getting set up with the domino, a kreg jig is 40 bucks if you go with the basic set up and just as fast.
I'm not saying the Domino doesn't have it's place and frankly I'd like to have one, in this instance, for this one project, it's overkill to purchase it if you don't have it and do not run into a use for it frequently
you still need support along the back of the shelf if you're going to have adequate support so either dado them in, or put a cleat on, a cleat IMO looks bad
I fully agree the domino is overkill for this project alone. If I were a professional trim carp or builder I think it would soon pay for its self in other projects. I am constantly finding more uses for my Fine MM as well and it was pretty expensive. It is hard to explain and justify the costs involved with some of the higher quality tools until you use them.
I have tied up a lot of money in Festool and now that I have them I can never image going back to my Dewalt, Porter Cable or Mikita sanders, there is absolutly no comparison. I can now sand almost totally dust free.
My Festool saw is the cleanest cutting portable saw there is (in my humble opinion), with that I now can handle sheet goods quickly and make glue ready carcass for my cabinets. Since I am a one man operation I do not share these tools. I do however let one of my friends come and use my Domino occasionally but not out of my shop.
BTW I also agree that is too much shelf to support any weight without cleating or dadoing a vertical back support. If and I don't know the intended usage, ie books no way without support, clothes or other light items no problem.
JF
I own several Festool tools, been mostly impressed with all of them execpt the 5" RO sander, It's "nice" but not worth twice the price
I have the 6" finish ETS 150/3 and the CF22 vac. am saving up for the RO 150 FEQ and maybe someday the Kapex when it becomes avaliable. I would like the screw gun but way to expensive, maybe after I wear out my DeWalt 18v and my Mikita impact 14v. I might look at it again. Their portable saw is outstanding but very pricey too, I have the small one and it does well for my needs. I have been using the CF22 attached to my router table and it works great. I have a Grizz 5hp but leave it hooked up to the table saw or the planer.
JF
3-0 ft shelves are going to bow under weight
According to my Taunton's Built In Furniture book, 3/4" ply can go up to 2 1/2' without a problem. If I put on a 1 1/4" rail plus nail through from behind, I shouldn't have any problems at all. At the point where I connect the left shelf to the front of the right shelf, I may have a weak point if I'm not careful with my joint. But I'm still not worried about any deflection in the shelf itself.
The best idea I've heard so far is the one to make the L out of one piece. That would be the best and I'll see if I can still do it. The Festool would be fun too but not currently in the budget.
If I can't do the L shape from one piece, I'll probably go with a 1/4" spline. I have some 1/4"x5" stock, I could use two of these for each joint have the grain going perpendicular to the joint line. I may also join the front rails with more than just glue, some type of mechanical joint to lock it all together.