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Discussion Starter · #1 ·
I'm going to be building a two person desk for me and my wife soon. I'm learning Google Sketchup to get the project going. I've never built anything that has to support weight. The footprint is about 8' x 8'. Here's a sketchup http://i.imgur.com/noQd3Le.png

It's going to be two pieces of wood long ways 3/4" thick (haven't decided oak/maple/cherry/etc... yet). The seam in the middle is what scares me I'm not sure what to do about that. A redditor suggested I biscuit join the seam which is probably what I'll do along with a couple leaf clamps. I'm just worried about it supporting weight. Any suggestions on how I can alleviate that, or if you think the whole design is flawed? Thanks
 

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where's my table saw?
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I wouldn't

I would not use glue and biscuits, rather use a vertical rail down the seam for added strength and to lap the pieces upon. For ease of moving there can be screws or brackets that attach to tops to the rail. Not that you couldn't make it all one piece, even with a stiffing rail glued in place, but there may come a time when it would be easier if it could be disassembled.

There is always the issue with biscuits in plywood that they may swell and cause small bumps in the top surface. So it's better to avoid them if possible. Glueing up the curved top will also be a challenge because clamps may want to slip in the curves, so a clamping band or ratchet straps may come in handy. The glue up will some take preparation, so have all your clamps and bands ready to go if you choose that method. A large flat surface or saw horses that are leveled with support boards will help.

Another idea is to put a low vertical "wall" between the 2 desks for utility reasons, shelves, hanging stuff, his 'n hers spaces etc. that's up to you. :smile:
 

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Discussion Starter · #3 ·
That's a much better idea. I'd much rather be able to take this thing apart. I put a 2x4 down the seam and will install a wire catch cabinet in the front. Here's some updated sketch pictures http://imgur.com/a/QPgjL I'm thinking about adding some design to the legs. Thanks for the help!
 

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where's my table saw?
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You still have too long an unsupported span. The idea was to provide SUPPORT in the middle.

George
You're probably right.
Let's overbuild this right outa the gate. Use 2 - 2 X 4's, one on each side and then just bolt them together for assembly They can be glued in place on each side, clamped and then mated together for the best fit. No screws will show on the top this way.
 

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Old School
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You're probably right.
Let's overbuild this right outa the gate. Use 2 - 2 X 4's, one on each side and then just bolt them together for assembly They can be glued in place on each side, calmped and then mated together for the best
fit. No screws will show on the top this way.
+1.:yes: That's a good idea in principle. Two by fours are unpredictable, and could go outta whack or crack and split. An alternative to the 2x4's would be to glue up ¾" plywood (2 per side). It's much more stable, and with some nice square edges, can get a good fit for the two piece tops. Tee nuts can be used on one side, and that would leave only machine bolts and washers needed to assemble.






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Discussion Starter · #7 ·
You still have too long an unsupported span. The idea was to provide SUPPORT in the middle.

George
I thought I was providing support by adding a 2x4 down the center and supporting it on both legs? I definitely do not want screws showing up top and I would like to be able to move it at some point in the next few years so I don't want to glue to the large pieces. I'll take a whack at using two of them side by side or using cabinetman's suggestion of plywood. I'm still nesting it so if I have some long slices I can use I'll go that route. Thanks for everyone's help. Updated sketch with two 2x4s: http://imgur.com/a/iY4kG
 

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Here's my 2¢ on the deal. Plywood on edge is structurally more stable than dimensional lumber due to the grain directions of the lamination layers. If you want an extremely strong "Beam" that will support that span with NO FLEX, then take two pieces of 3/4" x 4" x 8' plywood and a piece of 1/16"x 4" x 8' metal flashing like they use in roofing and sandwich it between the two piece of plywood. Use Gorilla glue to glue it all together and use screws to fasten it. You can counter sink them and fill the holes if you don't want em to show. When this 1 1/2" thick "Beam" cures a 8' long section 4" wide will easily support over 500lbs of weight with NO FLEX!!!
 

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Discussion Starter · #9 ·
Here's my 2¢ on the deal. Plywood on edge is structurally more stable than dimensional lumber due to the grain directions of the lamination layers. If you want an extremely strong "Beam" that will support that span with NO FLEX, then take two pieces of 3/4" x 4" x 8' plywood and a piece of 1/16"x 4" x 8' metal flashing like they use in roofing and sandwich it between the two piece of plywood. Use Gorilla glue to glue it all together and use screws to fasten it. You can counter sink them and fill the holes if you don't want em to show. When this 1 1/2" thick "Beam" cures a 8' long section 4" wide will easily support over 500lbs of weight with NO FLEX!!!
Thanks! I work I.T. in a weld shop so getting some metal is no problem. I should be done nesting in a couple hours so hopefully (I think I do) I'll have enough drop left for the support you're talking about.
 

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Old School
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Here's my 2¢ on the deal. Plywood on edge is structurally more stable than dimensional lumber due to the grain directions of the lamination layers. If you want an extremely strong "Beam" that will support that span with NO FLEX, then take two pieces of 3/4" x 4" x 8' plywood and a piece of 1/16"x 4" x 8' metal flashing like they use in roofing and sandwich it between the two piece of plywood. Use Gorilla glue to glue it all together and use screws to fasten it. You can counter sink them and fill the holes if you don't want em to show. When this 1 1/2" thick "Beam" cures a 8' long section 4" wide will easily support over 500lbs of weight with NO FLEX!!!
Adding the metal may increase the strength of the two pieces of plywood. But, my gut feelings are that just gluing and clamping the two pieces of plywood would be a better bond and stronger, than introducing a metal insert. The properties of a wood to wood bond IMO, are better than a wood to metal bond. I've never liked Gorilla Glue. I could be wrong.






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where's my table saw?
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agreed

Use wood or metal ...only.

If you use wood, make "L" braces, so you can access and screw not only into the underside of the top, but horizontally to attach the verticals together. The "L" braces will make it much easier to glue and attach them together rather than just vertical braces, which will require clamps. You can glue and screw them together without clamps for form the "L" shape. Personally, I'd just use hardwood 1 X 3" from the Home Depot, but select the straightest grain and boards you can find.
http://www.ehow.com/info_7909544_types-joints-degrees.html

OR just use angle iron/steel 1/8" thick X 1 1/2" faces. This is a ready made "L" brace. You must use a HHS drill for the all the screw holes into the metal. A drill press would make it soooo easy, but you may not have one. I'd use 5/8" sheet metal screws into underside of the top and 1/4" bots to attach the pieces together.
 

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bzguy
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If i were making this piece I would put a 45 degree 3/32" or so bevel on the two tops where they but for a small V-groove.
Unless thin and staggered like flooring, butt joints are kind of obvious and a no-no on the large flat surfaces of woodwork.
This creates what looks like an intentional architectural reveal and makes any minor "flush" discrepancies that may happen during or after assembly a non-issue.
 

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I like it!

If you can't hide it why try? Good idea, even if you use a hand plane and chamfer the edge with a few stokes... :yes:
 

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Old School
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If i were making this piece I would put a 45 degree 3/32" or so bevel on the two tops where they but for a small V-groove.
Unless thin and staggered like flooring, butt joints are kind of obvious and a no-no on the large flat surfaces of woodwork.
This creates what looks like an intentional architectural reveal and makes any minor "flush" discrepancies that may happen during or after assembly a non-issue.
I've done that as a design detail, but for the length of this top, I don't think I would fabricate a groove, or want a groove. Laminate tops are fitted almost seamlessly. Wood tops are fitted flush. No reason this top couldn't be done that way.






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bzguy
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Matter of taste I guess?
Personally don't like butt joints in any flat surface, not many people do this.
Laminate butt seams are usually one solid color, only done when necessary and usually mitered, like the corner of a picture frame.
Much more acceptable aesthetically, just my opinion .
Reveals add depth, dimensionality.
Another fix would be to miter edge on "his" desk, let "her" desk butt into vertical edge symmetrically 1 or 2" lower AND 1 or 2" shorter?
Ive seen many long room "wall to wall" wood office desk surfaces broken up this way, change the height and depth a little, then 8' runs bump into walls or sides of cabinet.
If it must be flush, yet another way is dado out slot and inlay two 4' lengths cross-grain pieces?
Just some ideas that look better, IMHO?
 

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