Table stability, any thoughts?

[Loki]

I'm working on a design for a coffee table for my own living room, but I'm not sure if the table is stable enough like this. For instance; would I be able to rest my feet on a corner (bad habits! but it's just in theory... really! ) without the whole thing falling over?

Other then that, any thoughts on the overall design?

[Onboard]

As long as the top is securely fastened to the base, I don’t see an issue based on apparent mass and relative dimensions. Feet only! I have doubts as to whether someone could sit on a corner. However, I’m not a structural engineer either.

[Gregory Paolini]

I'm working on a design for a coffee table for my own living room, but I'm not sure if the table is stable enough like this. For instance; would I be able to rest my feet on a corner (bad habits! but it's just in theory... really! ) without the whole thing falling over?

Other then that, any thoughts on the overall design?

I like it!

As far as stability, that's a good question - While scale rendering software will do great things to help our visions come to life, some of the more intimate questions remain unanswered until creation.

I would make a scale model, or perhaps a prototype out of poplar, or maybe even MDF to see how well it works out. Just looking at the rough dims, I think you'd be ok - But if you get right on a corner, it could get a little wobbly...

BTW - What redering software are you using? Is that Podium for Sketchup?

-gp

[Loki]

Thanks! A scale model or prototype would be a good idea, but I'm not sure how the overall weight of the table influences things too when you compare it with a model or prototype.

I guess I will just need to take a gamble here and hope it works out. If it doesn't work out, I can always change the base I guess.

As for rendering. I'm using Twilight Render. I have tried a lot of rendering software for sketchup and I like this one the most for doing quick renders. It's easy to use and produces some great results.

[PaulMarcel]

I like it as well. Actually said "whoa, nice" aloud when I opened it.

You'll definitely generate some torque with your feet up on the corner. As solid as the legs and tabletop look, it seems like you could make very strong joinery there (not reliant on just glue; mechanical as well). If the tabletop won't flex under your feet, it's up to the joinery. I don't see why you couldn't make sure that's beefy enough.

Again, nice design.

[Bobby Slack]

A good coffee table is one you can put your feet on.

[Beechwood Chip]

My first thought was:

1. estimate the weight of someone resting their feet at the corner
2. estimate the weight of the table
3. do the vector analysis to see if the table will tilt

• assume weight of feet is at the corner
• assume weight of table is at center of table
• assume fulcrum is directly above the leg nearest the corner, where it meets the floor
• work it as a lever if table weight x distance from fulcrum to center > foot weight x distance from fulcrum to corner, then you're good.

[Guest Mahoganus]

My first thought was:

1. estimate the weight of someone resting their feet at the corner
2. estimate the weight of the table
3. do the vector analysis to see if the table will tilt

• assume weight of feet is at the corner
• assume weight of table is at center of table
• assume fulcrum is directly above the leg nearest the corner, where it meets the floor
• work it as a lever if table weight x distance from fulcrum to center > foot weight x distance from fulcrum to corner, then you're good.

Nice one Beech Chip! So the world is not really full of dumb people haha:)

I like the style of the table as well and I would say just by looking at it,, it would be plenty enough stable and if not you could always add to the design with a counter weight to give it even more style

[Onboard]

I basically agree with your thoughts Beechwood. I could easily be wrong, but I was looking at it as one or two small areas (in square inches) representing a “point” of contact, in the area of the corner, that would generate a downward force (one or two vectors). It would probably include a little more than the simple weight of the feet alone. The force would be vectorized through multiple vectors through the table top and through the legs and base (i.e. not a simple vector as through a narrow beam). Also, as long as it is a rigid structure, the concern as I’m seeing it would be the force required to “tip” the table toward the resting feet. That is, the force required to lift the opposite corner or opposite side toward the resting feet. This would bring in the mass / weight offset of the table. Additionally, I see that as one moved away from the resting feet across the table, the weight of the table accumulates across the top and legs, which would offset the weight of the feet more and more. I’m sure there is software that can do the calculations as to how much force would be needed to tip the top or lift an opposite side.

Just some arbitrary rambling without much understanding.

[Lawrence Brown]

It's hard to describe without making you a diagram, but on each of those verticle legs, put some beefy mortise and tenon or other joints to keep the legs from sliding horizontally, then run a threaded rod right down the middle of those legs with a washer and nut on each end and tension them up. This would be a subassembly. You would hide the hardware with the top of the table and you could put plugs in the bottom so that you could get at the bottom nuts and rods again if you ever need to take it apart. As long as the rest of the tabletop is strong enough, you could sit on the edges of it and it should never move.

I'd suggest 1/2" threaded rod, since I'm guess those legs are about 2" thick. You may also want to add metal plates inside the top instead of washers, maybe 4 or 5 inches square to distribute the torque around a bit. It's probably overkill, but I like a bit of overkill now and then, especially where safety is concerned.

[Loki]

Wow, thanks a lot all, I see some great tips here that will help me a lot.

I don't really mind using screws here since everything would be out of sight.

The legs are indeed about 2" thick... all the measurements look a bit strange, but I'm using metric units when designing and used imperial for those pictures. Thought it would be more convenient on this forum.