Page 1 of 2 12 LastLast
Results 1 to 15 of 28

Thread: Is this sturdy enough or will it break?

  1. #1
    Join Date
    Jan 2005
    Location
    Denmark, Europe
    Posts
    219

    Is this sturdy enough or will it break?

    I've been tinkering with the design shown in the image.

    It's a low table/bench which will be used as a printer table.

    Everything is 40mm thick Wengé. The table top is 500mm deep and 1200mm wide.

    The legs are 500mm deep and 500mm high.

    Each leg is attached to the top with two 20mm thick stainless steel rods epoxied into the wood (20mm depth in the top and whatever is necessary in the legs). An alternative would be to drill through the top, and let the rods sit flush with the top face of the table top.

    As I hope the drawing shows, the legs are attached 50mm from the side of the table top, to avoid breaking of the grain in the top.

    I really like the design - I'd like it better if the legs were mounted flush with the sides of the top, but I doubt it'll hold.

    I also have my doubts about the design shown, as I fear the stainless rods will break the table top, due to racking. On the other hand, this table will only be used for two printers, so it will probably not see that much weight and movement.

    An alternative is to mount the legs to the top with domino-reinforced miters - which was actually my first choice - but I like this better.

    So, to sum up my questions:

    1) Will the table top break with the design with the legs 50mm from the sides, and "only" 20mm of the rods in the table top?

    2) Will the table top break with the legs flush with the sides and "only" 20mm of the rods in the table top?

    3) Will the table top break with the legs in any position and the rods all the way through the top face of the table top?

    4) Is this just a plain wrong design and the *only* way to do this without any stringers/stretchers is with reinforced miters?

    Any and all comments are VERY welcome!
    Attached Images Attached Images

  2. #2
    Join Date
    Dec 2008
    Location
    South Central Pennsylvania, USA
    Posts
    761
    I made a stand similar to that for easy disassembly when I was in college. Add a small stringer across the top of the legs at the back. You're not going to see it and it will significantly strengthen it. As is, with the pins, any side load is going to collapse it quite easily.

  3. #3
    Join Date
    Jan 2005
    Location
    Denmark, Europe
    Posts
    219
    Quote Originally Posted by Thomas Bank View Post
    I made a stand similar to that for easy disassembly when I was in college. Add a small stringer across the top of the legs at the back. You're not going to see it and it will significantly strengthen it. As is, with the pins, any side load is going to collapse it quite easily.
    How small? :-)

  4. #4
    Join Date
    Dec 2008
    Location
    South Central Pennsylvania, USA
    Posts
    761
    Had to look up metric conversions quickly...

    I'd say it was about the same thickness you are working with - say about 40mm x 80 to 100mm.

    It still wasn't a table that you wanted to set anything significantly heavy upon or lean against or it would have still pushed over fairly easily. But it was against the computer table on one side and within a couple feet of the wall on the other side, so it wasn't going to see too much abuse.

  5. #5
    Join Date
    Jan 2005
    Location
    Denmark, Europe
    Posts
    219
    So something like this: ?

    The extra stainless steel rod in the stringer will probably help a lot.
    Attached Images Attached Images

  6. #6
    Join Date
    Dec 2006
    Location
    Toronto Ontario
    Posts
    11,247
    Hi Neils, the stretcher will help for certain, however if you're only placing a couple of printers on it, where would the racking come from?

    It's 40mm wenge, it's going to be so heavy that nobody will be picking it up and moving it.

    If you're really worried about racking, join the sides to the top with wedged through mortise/tenons and forget about the pins, or use finger or dove tail joints.

    Regards, Rod.

  7. #7
    If this is going to be against a wall, is there any chance of making a solid back? It could be out if 1/4" ply rabbeted into the back to hide the edges. That will add a LOT of dimensional stability.

    You can also just use more rods, spaced closer together. Extend them deeper into the leg if you wish.

    Alternatively, you could just use wooden dowels - through and flush with the top or concealed.

  8. #8
    I wish I had more expertise to share, but I've got some ideas at least. Without any triangles or flat surfaces to prevent it, a table like that will fold up unless heavily reinforced.

    Running the steel dowels from the top of the top down four or more inches into the bottom would add strength, but I'm not sure if it would be sufficient. You would probably want to make the dowels about 13 mm (1/3 the 40 mm thickness), and for the exposed part between the surfaces, you might have a tube which would slide over the dowel. That gives you a little bit of a tenon shoulder effect. I still don't think it would be strong enough though.

    You could have a machine shop make up a plate with steel dowels welded to it which you would inset into the bottom of the top and attach with screws (allowing for wood movement), then connect the dowels to the inside of the leg using another plate. Allowing for wood movement in the cross grain/steel connections is critical, but it could be done without too much difficulty. I think that would be strong enough.

    If the table is not going to be visible from the back, you could add a thin (8 mm) sheet along the back near the top, but it would need to be fairly tall to provide support. My gut tells me at least 300 mm. The color might match the wall to visually hide it.

    You could do something with steel rods to make cross braces from corner to corner.

    Just some ideas. It's an inherently weak structure, but it could be very dramatic if it could be made to work. If it were me, I'd make a mock up and try to break it. You might need to use wenge for the joints to control for the wood type. That may lead to some ideas.

    $.02
    Please consider becoming a contributing member of Sawmill Creek.
    The cost is minimal and the benefits are real. Donate

  9. #9
    Join Date
    Jan 2005
    Location
    Denmark, Europe
    Posts
    219
    Quote Originally Posted by Rod Sheridan View Post
    Hi Neils, the stretcher will help for certain, however if you're only placing a couple of printers on it, where would the racking come from?
    Well, my 2½ yr old daughter would probably be the first to push it just for the fun of it, if it just wobbles a little bit

    So, to save my daughter - AND printers - I'll take the measures necessary to make this as stable as possible without sacrificing the simplicity of the design.

  10. #10
    Another idea is to attach it to the wall in back. If that would work in your situation, it would make it strong enough.
    Please consider becoming a contributing member of Sawmill Creek.
    The cost is minimal and the benefits are real. Donate

  11. #11
    Join Date
    Jan 2005
    Location
    Denmark, Europe
    Posts
    219
    Quote Originally Posted by Shawn Patel View Post
    If this is going to be against a wall, is there any chance of making a solid back? It could be out if 1/4" ply rabbeted into the back to hide the edges. That will add a LOT of dimensional stability.

    You can also just use more rods, spaced closer together. Extend them deeper into the leg if you wish.

    Alternatively, you could just use wooden dowels - through and flush with the top or concealed.
    A solid back is not an option (for me) as I want it to be as open as possible.

    Is the stringer/stretcher I added not enough?

  12. #12
    Join Date
    Jan 2005
    Location
    Denmark, Europe
    Posts
    219
    Quote Originally Posted by John Schreiber View Post
    Another idea is to attach it to the wall in back. If that would work in your situation, it would make it strong enough.
    Thanks for all your ideas John, however they don't suit me (sorry ).

    Do you also think the table is too weak - even with the stringer attached as shown in the latest pictures?

  13. #13
    Quote Originally Posted by Niels J. Larsen View Post
    Do you also think the table is too weak - even with the stringer attached as shown in the latest pictures?
    My gut tells me that the stinger would have to be quite a bit taller, but it doesn't have to be very thick. But I've never worked with wenge. You could make a mock up of the geometry of the table in two dimensions with construction lumber. It's plenty strong from front to back, but the concern is from side to side. You could just use building studs (2x4s in the US), bolt them together at the corners and experiment with the thickness of the stringer.

    40 mm has a very solid appearance. Somebody is going to climb on top of it one day to change a light bulb. If the actual strength doesn't match the appearance, it's going to go crunch.
    Please consider becoming a contributing member of Sawmill Creek.
    The cost is minimal and the benefits are real. Donate

  14. #14
    Join Date
    Mar 2004
    Location
    Coastal Virginia
    Posts
    647
    Quote Originally Posted by Niels J. Larsen View Post
    It's a low table/bench which will be used as a printer table.

    Everything is 40mm thick Wengé. The table top is 500mm deep and 1200mm wide.

    The legs are 500mm deep and 500mm high.
    You'll be fine IMO. I think some folks are being thrown off my the metric so let's convert (roughly);
    20mm = 3/4"
    40mm = 1 1/2"
    500mm = 20"
    1200mm = 47"

    Keeping in mind this a a printer stand and it shouldn't get a whole lot of abuse, Let's look at this:

    The top will be Wengé approximately 20" (500mm) deep, by 47" (1200mm) wide, by 1 1/2" (40mm). that's a very substantial piece of lumber! It's not going to flex under any reasonable load, much less the weight of two printers.

    Now you need to look at the legs/sides and the attachment. While you don't specify, I'm guessing from your pic that the sides are the same thickness as the top, 1 1/2" (40mm).

    I'd not waste the time or money on 20mm (3/4") stainless steel pins, hardwood dowel rods would be more than adequate. If it was me, I's sink the dowel 1" (25mm) into the top and about 2" (50mm) into the legs. With glue you'll have a very strong joint for the purpose. The stringer across the back would be a good idea and will add a god deal of sideways stability. If it was me, I'd make it about 4" (100mm). With the 1 1/2" (50mm) wide legs, 3/4" (20mm) dowels and the 4" (100mm) stringer it's going to be very stable.

    Mike

  15. #15
    Join Date
    Jan 2005
    Location
    Denmark, Europe
    Posts
    219
    Quote Originally Posted by M Toupin View Post
    You'll be fine IMO. I think some folks are being thrown off my the metric so let's convert (roughly);
    20mm = 3/4"
    40mm = 1 1/2"
    500mm = 20"
    1200mm = 47"

    Keeping in mind this a a printer stand and it shouldn't get a whole lot of abuse, Let's look at this:

    The top will be Wengé approximately 20" (500mm) deep, by 47" (1200mm) wide, by 1 1/2" (40mm). that's a very substantial piece of lumber! It's not going to flex under any reasonable load, much less the weight of two printers.

    Now you need to look at the legs/sides and the attachment. While you don't specify, I'm guessing from your pic that the sides are the same thickness as the top, 1 1/2" (40mm).

    I'd not waste the time or money on 20mm (3/4") stainless steel pins, hardwood dowel rods would be more than adequate. If it was me, I's sink the dowel 1" (25mm) into the top and about 2" (50mm) into the legs. With glue you'll have a very strong joint for the purpose. The stringer across the back would be a good idea and will add a god deal of sideways stability. If it was me, I'd make it about 4" (100mm). With the 1 1/2" (50mm) wide legs, 3/4" (20mm) dowels and the 4" (100mm) stringer it's going to be very stable.

    Mike
    Thanks for your reassurance Mike!

    I had the same impression and you're probably right - people are thrown off by the metrics. Sorry for that, but I don't do imperical

    I will use the stainless rods purely because of the look, so no wooden dowels for me..
    I think it'll make a great contrast to the black wengé.

    Thanks!

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •