Floating Shelves mounted with Dominos

[grbmds]

I recently saw the floating shelf concept shown in the attached picture. It appears that about 1"-2" of one edge of a live edge slab was ripped to serve as the wall-mount. It also appears that dominos were glued into the mounting strip with the remaining part of the dominos inserted into the rest of the shelf. I do own a Domino 700XL and I assume that 14mm dominos would be the appropriate size. Based on the XL manual the deepest mortise possible is 70 mm. I envision shelves that are maybe a total of 10" (254mm)deep So, my questions . . .

1. Is there a way of making a deeper 14mm mortise with the XL; up to 100mm deep? The ideal would be to be able to glue about 40 mm (just over 1 1/2") (of a 140 mm domino into the mounting strip and the remaining 100mm (almost 4") into hanging depth of the shelf. The shelves may be 5' long so I could probably use 5 dominos on each shelf (although I might not need that many if I can go into the shelf 100mm).

2. If I can't easily make a deeper mortise with the XL, then my question becomes whether a 70mm (2 3/4") deep mortise into the shelf would be sufficient to hold a live edge slab approximately 2" thick and 5' long?  Again, I can use 5 dominos over the 5" length. The majority of the weight would be the shelf itself as we don't plan to put anything real heavy on it.

 

[squall_line]

I found at least two different websites showing the technique.
https://www.bruceaulrich.com/blog/2020/4/7/diy-upcycled-floating-shelves
https://baynecustomwoodworking.com/diy-floating-shelves/

At least one method to deepen the mortise is a long drill bit.  I didn't read through either of those posts to see if they had any calculations or hints about spacing, depth, etc., so there may be good information in there.

I don't know how much I would trust 5 total dominos to mount an 8/4 x 10" x 60" slab, but that's just me.  It's "only" in the 30-ish pound range, depending on the species, but most of it is cantilevered.

 

[ChuckM]

1. Yes, You can make the 70mm deeper by using a drilling jig/guide bushing and a drill bit of the sane diameter. I've done something similar with my DF500.

2. I'd prefer deeper tenons (oriented vertically or double tenons).

 

[grbmds]

[member=57948]ChuckS[/member] I thought about vertical but, even with a 2" thick shelf there wouldn't be much wood at the top and the bottom. The same is true with doubling up. 14mm dominos are 1/2". It's hard to believe that 4 or 5 of them across the shelf wouldn't be stron enough. What would concern me more is the holding power of screws into the studs since there would only be 3 studs within a 5' long shelf. The online reference that [member=75217]squall_line[/member] gave showed using 4" long screws about 1/4" in diameter. Given that, even counter sunk, about 1" could be used by the backing piece on the wall and another 1/2" with drywall thickness. That leaves 2 1/2" into the stud.

 

[luvmytoolz]

Why not just use the metal mounts designed for floating shelves?

Thick timber cantilevered off some thin dominos just seems to be asking for trouble, even if technically adequate?

 

[Crazyraceguy]

I'm not seeing the point of all of the extra length(depth) in the shelf side? Especially since you would shorten the wall side to make it work. The weak point would be right at the joint. "Assuming" un-glued on the shelf side to make it removable, it will always break at the joint line, so how far it goes into the shelf is not really relevant.
If I were to do this, I would add a couple of Domino connectors in there to keep the shelf tight and call it good. (well personally, I would use Lamello Clamex, but this could be done by anyone with a DF700)
High shelves, put the hole on top, low shelves underneath.

 

[ChuckM]

CRG has got some good points there.

But if I were mounting those shelves, I'd get a construction lumber of similar size from a big box store (pretty cheap, about $15 - $18), and do a test run (add weight as necessary). If the mock-up shelf fails, I know where the weakest link is.

 

[woodbutcherbower]

Why not just use the metal mounts designed for floating shelves?

This ^ ^ ^ ^ ^ ^ ^ ^ ^ ^

 

[grbmds]

Testing for sure.

I could use the metal floating shelf brackets from Rockler. However, they depend on being able to drill a 3" plus hole into the wall studs. I can certainly get a bit long enough. However, ensuring that these holes are exactly 90 degrees to the wall surface seems a little iffy. I'm sure there are ways to do this, but it just seems like, if there is even a very small difference off 90 degrees, especially if the error is downward, problems will result.

The dominos are assured to be straight in both pieces of wood. Drilling a pilot hole into the wall for screws to mount the back piece to the wall doesn't seem to require quite the same level of accuracy and precision. Even very close should get the piece attached to the wall mounted flat.

Plus, after talking the whole thing over with my wife, we decided to just not do the shelves. Enough oak, maple, or cherry to do three 5' long shelves would require 30 board feet of wood; either 8/4 live edge slabs or boards or 4/4 glued together. At today's prices with my current access to good quality lumber that could be $600+. It doesn't seem worth it. Add $20 apiece for maybe up to 9 metal brackets or the cost of a 14mm Domino cutter plus the cost of 14 mm dominos (I don't own a 14 mm bit or dominos.) the cost isn't worth it. We just decided to find other ways to fill a blank wall that was created by a remodel; maybe with  a nice sofa table size table below and artwork on the wall. I am a turner and have more bowls than I know what to do with and my wife is a polymer clay artist (actually a multi-talented artist) who has a number of wall hangings and other art.

 

[Packard]

I would much rather use 1/2” diameter steel rods.  I would drill the holes for the shelf first, and I would go to a depth of 4” or so.  I would cut the steel rod to about 7”.

Insert 1/2” dowel center markers in each of the holes to mark the position of the holes to drill.

Drill into the studs.  For more strength add more rods, or switch to drill rods and using a torch, harden and temper the rods to spring temper.

I think the dominoes are going to be too short for this application. 5/8” will be used for the Sheetrock which will not add to the weight carrying capacity. I think you need to go into the stud by at least 2”.

 

[ChuckM]

Using metal rods, of course, is the common way people employ for such slab shelves, but it's missing the point in this case

If the OP is like me, I'd like to use my Domino machine as much as I can, and explore its use in many other applications where possible. I enjoy the challenge and learning process, and draw satisfaction from the outcome if it's a successful one. And that's how I grow as a woodworker.

I definitely would study and explore the use of dominoes (if I have a DF700) for that kind of shelf, failing which I'd then resort to the use of rods. I find deepening dominoes with a long drill bit pretty easy (which I've shown elsewhere in the forum)..

 

[Brian Livingstone]

I make as many floating shelves as the next man.  I use the Hovr Brackets.  They work extremely well.  They require two inch thick material, it is a bit of work, and they aren’t inexpensive. 

I think the 14 mm domino would be more than adequate for what I store on my floating shelves.  I think it would be a pleasant surprise how much weight say three 14 mm dominos could support.  The metal rods are not something that appeals to me.

I agree with one of the posters who is looking for opportunities to use their Domino XL.  I use my DF500 way more, and welcome the opportunity to bring out the XL.

Brian

 

[Packard]

Using metal rods, of course, is the common way people employ for such slab shelves, but it's missing the point in this case

If the OP is like me, I'd like to use my Domino machine as much as I can, and explore its use in many other applications where possible.

I think everyone prefers to use the equipment they own and are familiar with.  However, if you accept that 2” into the studs is the minimum that will give adequate support, then you need 2-5/8” depth of cut.  Will the Domino machine mortise that deep?  Are you going to glue into the wall?  Then the bottom edge of the shelf levers into the sheet rock.  Is the Sheetrock surface hard enough to sustain that pressure? 

The tenon will be sustaining loads in both shear (which it can probably deal with) and bending (for which I am suspicious).

I don’t think the domino machine is the right one for this.  I have a variety of doweling jigs and a biscuit joiner.  I suspect that I could hang a shelf with no load using either.  I also suspect that it would fail quickly.

Just because you have certain equipment, does not mean that you should use it. 

 

[grbmds]

Using metal rods, of course, is the common way people employ for such slab shelves, but it's missing the point in this case

If the OP is like me, I'd like to use my Domino machine as much as I can, and explore its use in many other applications where possible.

I think everyone prefers to use the equipment they own and are familiar with.  However, if you accept that 2” into the studs is the minimum that will give adequate support, then you need 2-5/8” depth of cut.  Will the Domino machine mortise that deep?  Are you going to glue into the wall?  Then the bottom edge of the shelf levers into the sheet rock.  Is the Sheetrock surface hard enough to sustain that pressure? 

The tenon will be sustaining loads in both shear (which it can probably deal with) and bending (for which I am suspicious).

I don’t think the domino machine is the right one for this.  I have a variety of doweling jigs and a biscuit joiner.  I suspect that I could hang a shelf with no load using either.  I also suspect that it would fail quickly.

Just because you have certain equipment, does not mean that you should use it.

The Domino 700 will cut a mortise to 70mm or around 2 3/4". However, the domino tenon is not being sunk in the stud. The original attachment I included shows the dominos being glued into the strip which is ripped from the backside of the shelf board. Then this strip, which appears to be about 2" is screwed into the studs. The guy who wrote the illustrating article used screws that were about 1/4" X 4".

However, at this point, the question is not going to be tested by me since we decided the overall cost of the 3 shelves, wood, dominos, and the required domino cutter, is more than we feel the value of the shelves for us is. I still believe it would work.

 

[ChuckM]

Snip.
I think everyone prefers to use the equipment they own and are familiar with.  However, if you accept that 2” into the studs is the minimum that will give adequate support, then you need 2-5/8” depth of cut.  Will the Domino machine mortise that deep? 

snip.

Just because you have certain equipment, does not mean that you should use it.

The depth of a mortise is not limited by the cutting depth of the DF700, or for that matter, the DF500. I've used my DF500 like a DF700 (to an extent) by deepening the mortises milled by the DF500. Sometimes, I use the 10mm dominoes made for the DF700, sometimes I make my own to suit the length. Others have done that, too. So the same applies to the DF700.

This isn't a case of "if all you have is a hammer, everything looks like a nail." I'm talking about EXPLORING expanding the capability of the DF700 or DF500 to handle applications that are beyond the imagination or intention of the designer of the machine.

But safety first. That was why I suggested testing it out with a cheap lumber. In some of my past projects when I had doubt about the joinery strength (whether it was loose tenons or other joinery), or tried to locate the weakest point, I used mock-ups where needed.

Everyone learns differently. I find learning outside the box just as satisfying as finishing a project to my own standards.

 

[luvmytoolz]

If you built it hollow with thinner timber like a torsion box it would be cost effective, and considerably cheaper than laminating stacks of thick timber. This would also greatly reduce the weight probably requiring less brackets depending on what items would be stored on the shelf.

When building things I always look at worst case scenarios, for example if one of the kids hang off it, so everything I do tends to be over engineered as I've found over the years no matter how well I make something, someone finds an inventive way to damage or break it.

And before people say you shouldn't always over engineer stuff, I disagree. Just before xmas we had a courier pull up in our driveway to drop a parcel off, and while watching from the security camera he backed out, but he started swinging out before he was fully out of our drive and the very thick and re-enforced fence post he hit took off the entire front end of his van! Damage to the fence, a tiny paint scrape on the post! If I hadn't over engineered it I'd be looking at a new fence!

Over engineering vindicated!

 

[Crazyraceguy]

[member=75933]luvmytoolz[/member] I have built a bunch of them like that over the years. Usually just plywood strips as the frame and 1/4" MDF skins. Then they get veneered or laminated with HPL.
I've done the solid wood version a few times, but drilling the holes is more of a pain than building pockets into them. They turn out far lighter that way too, then the brackets are not supporting as much shelf, leaving more strength for stuff