Joints

[Greg Guarino]

Planned desk "bridge" to hold video monitors and speakers:

I have made a few modifications to my Sketchup drawing and have now bought the lumber. I have in fact lowered the video monitor height - as someone he re suggested - but not as much as some people advised. The height will end up being the same as I had been using for a couple of years, so apparently I like it that way. :)

After asking here about how I might bend some solid wood edging to finish o ff the curved ply edge, I decided to just go with solid lumber. But that br ings up a few other issues.

I had originally planned to use rabbet joints for the cubbyhole joints unde r the speakers, as shown here:

... and I may still. I would make them with a router. But now I'm consideri ng whether I might experiment with lock-miter joints. Any advice? Are they tricky to set up? Do you consider the side view of such a joint ugly? (ther e won't be any face frame)

Then there's the (bigger) question of how to fasten the cubbyhole upright p iece that's closer to the middle of the shelf. In the drawing it's shown as a butt joint, which I won't be using. But what to do instead? It will be e nd grain to long grain, if that's not obvious.

I'm reluctant to use a dado, as I feel it might weaken the shelf. Here's wh ere someone will likely tell me that as long as the dado is filled - snugly - it will be just as strong. Is that true?

There won't be any stress on the joint, so it may not matter what I do. But I like to improve my technique. I could use biscuits. I'm aware that many claim they provide mostly alignment, rather than holding power, but simple gravity would almost be enough in this instance. I could also use dowels, w hich I think might not be a bad idea.

Any thoughts?

[Leon]

Yeah, A dado will not significantly weaken the joint unless you plan to stack several hundred pounds on it.

I would ditch the rabbets on the vertical pieces all together. I would cut the dado for the inner vertical pieces to fit into, and put a wider

3/4" wide rabbit on the ends of the horizontal pieces to accept the full width of the short vertical pieces.

AND I would limit depth for the dado and rabbets to 1/4" deep, assuming you are working with 3/4" thick material.

[dpb]

Clearly there's some loss of strength but as you note if the joint fits properly the inset material counteracts almost all of that by resisting the bending that would occur on loading the shelf with the dado cut but still empty. As Leon says, for it to matter would be at the loading limits of the material itself which you'll not be near approaching.

I don't disagree with his other design mods either, for appearance and simplicity (why make two cuts when one will do?) altho I'd probably opt for a little deeper than 1/4" but that's just personal preference--it won't make a whit of difference functionally.

I like the 45 miter lock joint if that's what you're meaning above...it does take matching the height precisely and careful work but is really neat when done well.

HOWEVER, (and it's a BIG one here) you can't cut one of these with a handheld router and with the size of your shelf it'll take a really large router table to have the facility to cut it accurately. So, I'd say it's not a practical option for this piece.

[whit3rd]

Against racking, I"d want to put a bit of a back on the columns (maybe just a 4" skirt board), and would consider it a bonus if it could get a power strip bolted to that, under the shelf where it's not visible. You could do that with ugly wood, and paint it black.

I'd prefer to see long grain, would consider using biscuits and a 45 degree cut, but the rabbets are OK. You can trim-rout the endgrain, and it will take stain/finish dark to make a pleasant design feature.

If there's a back/skirt, the butt joint (perhaps with biscuits) would work fine. I'd worry about racking, though, if there's no back; could you make it a tad wider, and put some pencil drawers in it? Or even DVD/CD cubbyholes?

Making a dado look neat from the front is... hard. I'd want to avoid that, or make it look like a decorative feature (dovetail?). Blind dado is good, but don't expect strength when gluing one.

[Greg Guarino]

ght the lumber. I have in fact lowered the video monitor height - as someon e here suggested - but not as much as some people advised. The height will end up being the same as I had been using for a couple of years, so apparen tly I like it that way. :)

sh off the curved ply edge, I decided to just go with solid lumber. But tha t brings up a few other issues.

under the speakers, as shown here:

dering whether I might experiment with lock-miter joints. Any advice? Are t hey tricky to set up? Do you consider the side view of such a joint ugly? ( there won't be any face frame)

ht piece that's closer to the middle of the shelf. In the drawing it's show n as a butt joint, which I won't be using. But what to do instead? It will be end grain to long grain, if that's not obvious.

s where someone will likely tell me that as long as the dado is filled - sn ugly - it will be just as strong. Is that true?

But I like to improve my technique. I could use biscuits. I'm aware that m any claim they provide mostly alignment, rather than holding power, but sim ple gravity would almost be enough in this instance. I could also use dowel s, which I think might not be a bad idea.

Sounds like good advice, especially since dadoes are in my skill set. One o f the things I like about dadoes is that once I cut them properly there is basically no chance of misalignment.

[Greg Guarino]

ght the lumber. I have in fact lowered the video monitor height - as someon e here suggested - but not as much as some people advised. The height will end up being the same as I had been using for a couple of years, so apparen tly I like it that way. :)

sh off the curved ply edge, I decided to just go with solid lumber. But tha t brings up a few other issues.

under the speakers, as shown here:

dering whether I might experiment with lock-miter joints. Any advice? Are t hey tricky to set up? Do you consider the side view of such a joint ugly? ( there won't be any face frame)

ht piece that's closer to the middle of the shelf. In the drawing it's show n as a butt joint, which I won't be using. But what to do instead? It will be end grain to long grain, if that's not obvious.

s where someone will likely tell me that as long as the dado is filled - sn ugly - it will be just as strong. Is that true?

But I like to improve my technique. I could use biscuits. I'm aware that m any claim they provide mostly alignment, rather than holding power, but sim ple gravity would almost be enough in this instance. I could also use dowel s, which I think might not be a bad idea.

Yes, my router table is a tad under 6 feet deep. :) Many tads in fact. That is valuable advice. Thanks.

[Greg Guarino]

st a 4" skirt board), and would

he shelf where it's not visible.

under the speakers, as shown here:

in/finish dark to make

ht piece that's closer to the middle of the shelf. In the drawing it's show n as a butt joint, which I won't be using.

k fine. I'd worry about

ut some pencil drawers in it?

at, or make it look like a

rength when gluing one.

I'm not too worried about the look of the dadoes. It's my own desk, after a ll. But I will consider the possibility of racking. In my current design th e middle "leg" will be 3.5" wide and hollow; I may use it as a wire conduit from under the desk.

I don't think I will add a full "skirt", as the mixer (the angular thing on the right hand side of the desk) has many connections in the rear, some of which are near the top edge and angle upwards a bit. But if nothing else, I will try to design in a couple of triangles or something.

[Leon]

LOL, You should come watch me put a cabinet together. I use front and back face frames with groves and dados cut in the rails and stiles. And I have dados in the sides of the cabinet panels to accept bottoms, tops, and some times fixed shelves. The sides, tops, and bottoms fit into the dados and groves in the faces of the face frames. It all has to be a perfect fit to go together.

A simple cabinet has 12 groves/dados that all get glued up in one process.