Are there any golden rules for making solid and stable tables?

[ol_london]

I have been asked to make a dining table with quite thin wooden legs (45mm diameter) but no visible apron or stretchers. They want to copy a look they have seen online

It’s going to be a challenge to make a table that doesn’t wobble. Table is 140 x 75cm, oak.
It has made me wonder are there any golden rules for how to make legs/frames that are sufficiently stable? I mean like ratios between table leg thickness and apron sizes, at what point you need a stretcher or when is a stretcher unnecessary?

There are so many ways to build a table, but how much of the joinery is actually needed?

For this table I am thinking to mortise the whole leg through the top so it is supported 360 by the top, forming a 25mm thick ‘collar’ around the highest part of the leg to prevent them wobbling.

 

[CaptainBudget]

Assuming your design does allow for rock solid joints on the top, at 45mm DIA those legs are going to flex and without using a steel core there is nothing you can do about this.

Your biggest issue is the joint at the top of the leg has to resist a Moment generated whenever the leg is twisted (i.e. dragged across the floor or bumped into), hence why traditional joinery has aprons as they allow for full-height tenons that offer maximum resistance to this twisting force.

Your method sounds like the least rubbish option to me, but I genuinely can't think how you'd pull this off on anything bigger than a side table without it flexing (and those leg joints won't be particularly strong...)

Only other option I can think of is using a wedged mortice and tenon (wedging the top of the leg from the top surface of the table, you could use a piece of contrasting timber for a feature detail), but that has to be cut 100% spot on or it will still wobble...

 

[NickM]

I'm no expert so feel free to take what I say with a large pinch of salt, but that sounds very weak indeed to me. I could see a the legs falling off if someone dragged the table or bumped into it. To build a table without stretchers would require some kind of hidden structure (e.g. steel).

 

[Dee J]

There's a reason why traditional tables are built as they are. Stepping this far from the traditional will require ingenuity and probably some steel reinforcement. Strong enough for dining is fine, but tables get dragged, leant-on and much more.

 

[TheTiddles]

Sure that’ll be plenty strong enough to support its own weight and look good in a picture, not much longevity as a practical table I suspect.

I don’t think there are “rules”, but the compromise between function, appearance, durability, material use and manufacturing ease has been done for a good few hundred years, so looking around will tell you what works.

I’m all for floaty looking tables and with care you can make a table that looks light yet is still durable

 

[Jameshow]

I suppose you could cut out 6" circles of oak same as the top, turn them on a lathe to taper one side and then glue to the table the legs can then be tenoned (perhaps wedged) I to the 2" thick oak.

You won't see it at eye or seating level.

Cheers James

 

[ol_london]

I suppose you could cut out 6" circles of oak same as the top, turn them on a lathe to taper one side and then glue to the table the legs can then be tenoned (perhaps wedged) I to the 2" thick oak.

You won't see it at eye or seating level.

Cheers James

Thanks. Actually I am thinking this too. To make a mounting plate out of the same oak 25mm glued on which gives me 50mm thick base in total to forstner a 45 diameter ‘mortise’. Glue and screw the legs through that and it’s a bit like an apron...sort of.

 

[ol_london]

Assuming your design does allow for rock solid joints on the top, at 45mm DIA those legs are going to flex and without using a steel core there is nothing you can do about this.

Your biggest issue is the joint at the top of the leg has to resist a Moment generated whenever the leg is twisted (i.e. dragged across the floor or bumped into), hence why traditional joinery has aprons as they allow for full-height tenons that offer maximum resistance to this twisting force.

Your method sounds like the least rubbish option to me, but I genuinely can't think how you'd pull this off on anything bigger than a side table without it flexing (and those leg joints won't be particularly strong...)

Only other option I can think of is using a wedged mortice and tenon (wedging the top of the leg from the top surface of the table, you could use a piece of contrasting timber for a feature detail), but that has to be cut 100% spot on or it will still wobble...

Thanks. By steel core, do you mean something running through the leg like a rebar, up into the top? Not sure I get it.

 

[recipio]

I presume the legs will be splayed giving that 'mid-century modern ' look now popular. I made a set of mid century table stands once and used the threaded rod brackets which splay out at 12.5 degrees. They were hard to source and I ended up getting them in the US which meant I had to use 1/4 -20 threaded rod epoxied into the legs. It worked fine and is as solid as could be hoped for. Using them on a table will work but it may flex a little. You don't say if the legs will be turned which will add to the flexing. Best of luck.

 

[thetyreman]

out of interest how will you stop the oak table top from warping? I've seen quite a few tables with hairpin legs that ended up warped.

 

[danst96]

Not sure of the design you are going for but I'm busy building a table. The legs are from a 2 sheets of 18mm birch ply cut to shape and then has a hidden apron/stretcher (I'm not sure of the correct term). This sits in a slot and will be clamped from both sides to give maximum strength. I'm a bit dubious as to how well it will work long term but I've put it together and it seems to be pretty stable. Furthermore the centre stretcher piece will protude through 2 grooves in the table top so you can see two strips or the ply end grain which I hope will add to the strength. Sorry this probably doesn't add anything to the OP as it's probably a totally different design. I don't mean to hijack either but I'd be glad of anyone's feedback as it's similar issue to the OP .

 

[paulrbarnard]

What about X shaped stretchers? They would not be visible from the edges and would provide support for the top as well as some meat for a decent tenon.

 

[ol_london]

What about X shaped stretchers? They would not be visible from the edges and would provide support for the top as well as some meat for a decent tenon.

You mean connecting the legs diagonally?

 

[ol_london]

out of interest how will you stop the oak table top from warping? I've seen quite a few tables with hairpin legs that ended up warped.

I’m not sure why it would warp, the oak is kiln dried and it’s only 75cm wide. Do you think adding battens or a hidden apron (say 2cm thick well set back) would stop that.

 

[ol_london]

I presume the legs will be splayed giving that 'mid-century modern ' look now popular. I made a set of mid century table stands once and used the threaded rod brackets which splay out at 12.5 degrees. They were hard to source and I ended up getting them in the US which meant I had to use 1/4 -20 threaded rod epoxied into the legs. It worked fine and is as solid as could be hoped for. Using them on a table will work but it may flex a little. You don't say if the legs will be turned which will add to the flexing. Best of luck.

I wasn’t going to use those angled metal mounting plates that take a threaded rod because I have seen them wobble when used any higher than a coffee table.

 

[Fitzroy]

Recently made this bench. Legs are 45mm diameter tapered to 35mm, into 41mm diameter epoxied and wedged through mortices, top is 44mm thick. Bench is 350mm deep, 440mm tall, and 1800mm long. I epoxied them to ensue zero movement of legs in the mortices.

The bench flexes along its length ever so slightly when two people sit close together in the middle. You can deflect the legs somewhat under reasonable pressure. I did quiet a lot of experimenting when building it and although thinner legs and smaller mortices would have, I think, been strong enough the flex would have made me concerned each time I sat on it. With legs twice the length on a table I think it’ll wobble and shake no end with even light use.

 

[CaptainBudget]

Thanks. By steel core, do you mean something running through the leg like a rebar, up into the top? Not sure I get it.

Yep, a solid steel bar running through the centre of the leg to stiffen it. You'd need a means of cutting said hole and it's not really practical, but it's all I could think of.

Regarding warping of the top, yes your material is kiln dried but the humidity will vary throughout the year, and this causes seasonal moisture changes in the timber. It may not be much but the effect can be very pronounced depending on how the stock was sawn at the mill. The traditional method is using the legs and aprons as a frame to restrain the top (using cabinet-maker's buttons or similar) whilst allowing seasonal expansion and contraction; ideally making the top with quarter sawn stock as this is least likely to "cup."

 

[paulrbarnard]

You mean connecting the legs diagonally?

Yes

 

[MickCheese]

Guitar necks are kept straight with a truss rod of either steel or carbon fiber routed into a grove with the resulting grove filled in with a piece of matching wood (or not matching and called a skunk stripe). That would keep your legs straight, but I cannot see how you would brace the legs against the sideways force every table is subjected to when leaning on it, or more importantly dragging it across the floor. My wife has managed to loosen the bolts in the legs of our very substantial oak dining table by dragging it to move it, and that has a fairly deep skirt. Good luck!

 

[Pineapple]

I have been asked to make a dining table with quite thin wooden legs (45mm diameter) but no visible apron or stretchers. They want to copy a look they have seen online

It’s going to be a challenge to make a table that doesn’t wobble. Table is 140 x 75cm, oak.
It has made me wonder are there any golden rules for how to make legs/frames that are sufficiently stable? I mean like ratios between table leg thickness and apron sizes, at what point you need a stretcher or when is a stretcher unnecessary?

There are so many ways to build a table, but how much of the joinery is actually needed?

For this table I am thinking to mortise the whole leg through the top so it is supported 360 by the top, forming a 25mm thick ‘collar’ around the highest part of the leg to prevent them wobbling.

First Golden Rule = "DON'T MAKE BOOMERANGS" = If you are ever going to make Anything for some-one else; make extra-sure that it is well designed & superbly executed - so that there is no possibility of it being returned to be repaired or replaced AT YOUR EXPENSE !! - If your client asks you to make anything which You think is an inferior or impractical design then the safest Golden rule is to explain to them that "Function Beats Form" - How well the item will perform in service is Absolutely More Important Than How Stylish It Will Look.....( Don't make Boomerangs )