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Thread: How do Cado wall unit cabinets hang?

  1. #1
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    How do Cado wall unit cabinets hang?

    I saw a Poul Cadovius mid century wall unit on 1stdibs that has a cabinet for books or records, and I canít figure out how the unit will support all that weight, and I looked but i could not find a clear answer online.

    I read that the early units are all wood. Iíve seen how right angle wooden supports hold up the shelves and later cado units use metal ďarmsĒ and pins to support shelves, but I canít find how the heavy cabinets are hung.

    Design within reach has new cado Royal system units and the instructions online say that a metal pin set 1Ē into angled holes in the vertical wooden support sticks out some unspecified amount and fits into a hole on the back of the cabinet.

    Does anyone have or has anyone seen a wooden cado wall unit system and can tell me how the cabinets are supported?

    im thinking itís a few dowels set into angled holes in the vertical wooden supports that sit in holes on the back of the cabinets, but that doesnít seem like it could hold a lot of weight.
    Don't forget the struggle Don't forget the streets

  2. #2
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    After studying pictures on line and finding the same (unsurprising) absence of imformation, I would suggest there are mushroom-head steel pins on the back of the units. This style of pin will lock both shelves and cabinets in place tightly. You may have to experiment to get a system to work. An alternative is to purchase a steel shop system and cover the components with timber. That way the engineering is done. Cheers

  3. #3
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    Quote Originally Posted by Evan Ryan View Post

    im thinking it’s a few dowels set into angled holes in the vertical wooden supports that sit in holes on the back of the cabinets, but that doesn’t seem like it could hold a lot of weight.
    You got me curious and I started researching too. I agree with your thought process based upon all of the images I can find; its an angled dowel pin in the back of the cabinet that is received by a corresponding angled hole in the track.

    As for the concern on the dowel strength (skip to the bottom now if you like), I think this set up would actually be pretty strong. I have found a lot of research / testing on the the shear strength of a dowel as it relates to timber framing, but very little testing of dowels of less than 1" diameter. information is also out there on shear strength of wood species in psi, which you could extrapolate with more math than I am likely to attempt. Here are two somewhat applicable reports:

    http://support.sbcindustry.com/Archi...u5o371pv47cgf3

    https://www.agriculture.purdue.edu/f...96912c_000.pdf

    Wade through at your own risk.... A couple of thoughts on the reports and the joints:
    - the first report appears to be more applicable, albeit much harder to read.
    - major take away; there is a KS12-50 sample which is a 1/2" white oak dowel... most applicable to this cabinet set up
    - There doesnt appear to be major deflection (and certainly not failure) up to two kilonewtons. Dowel is failing close to 3 kN and collapsing shortly thereafter. 1 kN = 224 lbs.
    - Seems a 1/2" white oak dowel will support over 400 lbs easily in true shear, and will be support (but deflect) as you load up to 650 lbs before shear failure... (wow, that feels like a lot!)
    - second report deals more with joint strength than dowel strength and is dealing in psi, which is tougher to decipher, but Table 4 uses straight pounds for loading and lists joint deflection.
    - 3/8" dowel joints deflect in thousands of an inch when loaded up to 150 pounds. Seems to coincide with the other report.


    My summary, for what it is worth...
    - Assuming the "rails" are of good quality and attached solidly to the wall, its a safe assumption that cabinets supported by two dowel pins are going to easily hold more weight than you would ever practically load.
    - The design of the cabinet system also gives you advantages;
    1. Noted in the reports that all of the dowels are installed at right angles and deflection / failure usually starts with "pull out" caused by compression of the dowel and loosening of the joint That is mitigated with the angled dowels here, as the dowel would have to completely fail or rotate up to withdraw from the joint. Both the weight of the cabinet and the fact that the bottom of the cabinet resists rotation by resting against the wall rails prevent this. In fact, the taller the cabinet section, the more it will resist this rotation.
    2. Further, the angle of the joint actually makes the area of the dowel slightly larger in the direction of shear than the 90 degree orientation studied on the attached reports
    3. The rails are obviously oriented with grain perpendicular to shear; make sure your cabinets are also constructed with the dowel going into perpendicular face grain (no end grain).


    Short answer; the dowel will not be the weak link if the joints are properly constructed.

  4. #4
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    The photos of the wooden cado shelf supports show a few dowels on each shelf support and the vertical rails look like they have receiving holes about every inch, so I bet the cabinets are hanging on at least 5 dowels on each side.

    thank you for your research.

    im still searching antique shops for examples or someone whoís seen the back of these cabinets.
    Don't forget the struggle Don't forget the streets

  5. #5
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    Finally found a picture that shows a disassembled cadovius wall unit and I can clearly see three angled dowels coming from the top of the cabinet. Are there 3 more dowels at the bottom of the cabinet? I Think so.
    Attached Images Attached Images
    Don't forget the struggle Don't forget the streets

  6. #6
    Installing a System Cado wall unit with 3 sections. Picture 1 shows two sections in house they came from. Picture 2 shows the wall where the 3 sections will be hung contiguously. The wall is ľ” blue board with a 1/16” plaster skim coat on top.


    The attached .pdf shows the rail locations (2 per section) relative to the wall studs.


    There are 4 predrilled holes per rail. Rails will be mounted with 2.5” wood screws where there is a stud behind the rail location (rails 1, 3 and 5), and toggle bolts (3/8” or ľ”) with a flat head 3” screw where there is no stud behind a rail (rails 2, 4 and 6). Screw and toggle bolt size is defined by the diameter of the predrilled holes in the rails.


    The plan assumes the studs are exactly where shown in the .pdf. BUT, not able to guarantee this, worst case is that the 2 rails for any one of the sections must be attached using 8 toggle bolts (4 per rail).


    A google search found a document on shear and tension forces referenced in a few other forum threads that discussed System Cado. See https://www.factsfacts.com/MyHomeRep...rstrengths.htm


    The attached spreadsheet shows worst case calculations for each of these forces for 1 cabinet and 3 shelves all with nothing in the cabinet or on the shelves. Shelves sit on top of side supports (see Picture 3), effectively being an extension of a shelf.


    Neither shear force nor tension force appear to be an issue. The tension force is dramatically reduced by the shelf side supports.


    Is my analysis of the shear and tension forces correct? That is, for worst case (all toggle bolts), will 8 toggle bolts be sufficient to support the weight of 1 cabinet and 3 shelves?


    I appreciate any feedback on my analysis.

    Analysis follows - I was not sure how to add a .xls. What I did add with a copy lost all spacing so below is a picture of the spreadsheet information.

    IMG_5833.JPG

    Plan - again a picture since can't add a .pdf

    IMG_5834.JPG



    P1 - Wall Unit In Old House.jpgP2 - Wall For Wall Unit.jpgP3 - Wall Unit Showing Bored Holes For Brackets .jpgP4 - Cabinet with doweling pins.jpg
    Last edited by Justin Ewing; 06-21-2022 at 12:08 PM.

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