Rules of thumb for French Cleats?

[Scott Winners]

I feel pretty good about the half of the cleat system that gets fastened to the wall. If the hanging item is heavy enough I can use a wider board on the wall to get two screws per stud.

I am tripping over, haven't found any guidance online, about the width of the cleat that goes on the back of the cabinet, or how to fasten it securely.

My immediate concern is a till for handsaws, nominal 30" wide, 40" tall and 12" depth. The case work is going to be 4/4 hardwood. Total weight, saws, some files, a couple sets, the hardwood case, should be well under 100#, maybe 60-70# tops.

On the wall I am thinking 4/4 hardwood, 3-4" wide and 30 inches long I will be able to get two 3" screws (I like the #9 GRK uber grade at 870# shear each) into each of two studs, 4 screws, 3400 some pounds could hang from that. I think at 100# of cabinet and content the 3-4" wide cleat half on the wall shouldn't mar the 1/2 drywall.

But what about on the back of the case? I am not going to have a lot of scrap at the end of this, so getting crazy with mortise and tenon joinery to incorporate the cleat half in the case with joinery is going to require a lot of thought. Can I just look at the shear strength of #8-10-12 screws (which seems to be based on threaded penetration into the lower layer) and then use some glue for overkill? Fasten directly to the back of the case?

Please? I am not going to have enough scrap to cook anything bigger than about a 4" bluegill. I do have enough material (seasoning in my shop for two years) to put a brace across the back top and bottom, and make the cleat. I can get some more beech from the store, but I am not in a position to wait two more years.

I have been worried about the 30" span of the cleat half on the cabinet back bowing, but it occurs to me once the cabinet is hung in the mating cleat on the wall the 30" span on the cabinet back will be supported by the cleat half fastened to the wall every 16 inches.

I did search here quite a bit in the old threads and haven't found this discussed before.

Thanks

[Kevin Jenness]

Can I just look at the shear strength of #8-10-12 screws (which seems to be based on threaded penetration into the lower layer) and then use some glue for overkill? Fasten directly to the back of the case?

Yes. It's a cleat. You can make it out of some other wood, it will work as well and no-one but you will know. Run it full length across the top of the box. Some screws sunk solidly into the top and side back rabbets will suffice. Many a kitchen cabinet has hung on less.

[Lee Schierer]

You can make the cleats out of any wood or metal. They can be any width you wish to use. Because of their superior strength, I don't use anything other than GRK screws. The cleat on the back of the cabinet can be glued on as long as the back panel can move with seasonal moisture changes if it (the back panel) is regular lumber. No one but you and whomever eventually takes down the cabinet will ever see the cleat, so the type of wood used really doesn't matter.

[Curt Harms]

I made two cabinets out of 3/4" oak ply. I made the cleats out of 3/4" ply as well, about 3 1/2" wide. the part on the cabinet is flush with the back and top. The part on the wall is fastened with 1/4" lag bolts. The one cabinet has quite a few books in it so not light and nothing has moved for 20 years.

[Jim Becker]

Even a narrow cleat can be "mighty darn strong" because of how weight is distributed across its length. So what's most important is how well it's fastened to the "whatever" it's going to hold up on the wall. And as with your wall cleats, wide enough to take multiple fasteners into the support structure of the "whatever" makes for handling higher loads. As long as the "hang line" is consistent, you can use different widths for different "whatevers" that are going to be hung based on your gut feeling about how beefy it needs to be. And this is a great way to leverage those shorts and other shop scraps. :) :D

[Randy Heinemann]

I make the cleat on the wall and the back of the cabinet the entire width of the cabinet (minus the sides of course). Also, when I'm designing wall cabinets I usually provide a recess in the back of the cabinet the depth of the wood I will use for the cleats. That way it fits into the frame of the cabinet, permits mounting the cabinet tight to the wall, and potentially gives additional possibilities for fastening to the cabinet frame. I wasn't sure whether that was your intent.

I usually make both cleats the same width, but the cleat on the cabinet can be narrower as long as it's wide enough to securely accommodate screws, or other fasteners. 3" -4" is great.

Also, if possible, cutting both cleats from one board is ideal as then a bevel cut is made and the two pieces fit tightly together. This isn't a requirement but I like the concept. It wasn't clear you were going to do this.

Finally, like other responses, the wood doesn't have to be the same as you used for the cabinet unless that's important to you. Any wood will work, including construction grade pine, as long as there are no imperfections which might weaken the strength of the wood.

[Warren Lake]

I use baltic birch for both the cabinet and the wall, Screws into the wall located more to the top of the cleat. cabinet back if a small cabinet with a 1/4 back cleats are glued then stapled all the way around into the rabbet the back sits in. The odd time a wall will be out and depending the cabinet may not drop right down and bottom out on the cleat. This will be more of a concern when a number of cabinets are mounted this way in a row

[George Yetka]

I have had cleats for a few years now but havent had any cabinets until recently. I got a project that had about 60 very nice MDF cabinets fully laminated with good hardware and locks. I grabbed a couple for the garage as they were brand new or just about. They were actually installed with french cleats only about 2-1/2" at the widest on 3/4 Ply. So when I got them home I put it right on the wall. I did end up sinking a couple screws into the 9x1-1/2 screws into the back of the cabinet and into the wall cleat. The cabinets on there own are 100lbs a piece. before I filled one with finish469441