# Glued joint to lever ratio (coffee table)



## drpdrp (Oct 19, 2012)

Designing a coffee table that 18" of "free" empty space under it without braces for the legs. (so something can slide under).

At about 20" it starts seeming pretty high for a coffee table- although I guess it is sort of a soft line there…

This table will likely get slid around more than normal.

So, if the legs are 18" without support- how big of a joint do you think I need to keep the legs from wanting to break off?

This is roughly the sort of design I have in mind: THIS

I the legs were 4×4 and the top was 2x would a 2x rail provide enough strength? I think it would look alright and that probably gives about 21" actual height?

Thoughts?


----------



## jmos (Nov 30, 2011)

If your going 4×4 legs and 2×4 rails you will have plenty of strength if you use an mortise and tenon joint. At those proportions, a pegged, or draw-bored joint would look nice and add some additional strength.

That will be one hefty table!

I would not recommend trying to glue the legs and rails as a butt joint (long grain to end grain), you'll get no strength from that, which is what I infer from your title.

You could also look at pocket joinery, dowels, or even metal brackets designed for this application. You'll have a lot of meat between those boards for a joint.


----------



## oldnovice (Mar 7, 2009)

*Jmos* hit the nail on the head, that is going to be one hefty coffee table!

Have you considered building the legs as a square tube to reduce the weight and possibly the cost? If you make hollow legs you could possibly hide some casters inside and make the sliding easier.
You could even do that with the top to give the illusion of that thickness and also reduce the weight.

If you don't use casters, hidden or otherwise, make sure you have a good size chamfer or step on the bottom of the legs where they touch the floor to reduce splitting out the bottom edge when sliding the table, if you can!

Use table top mounting clips to hold the top to the rails to allow for movement of both.


----------



## bigblockyeti (Sep 9, 2013)

+1 to the table being hefty. A mortise and tenon would provide substantial strength with the sized lumber you're planning on using.


----------



## wormil (Nov 19, 2011)

What would you use for a dining table, 8×8 timbers? Don't over think it. The strength is in the design, not the individual components: 3/4" aprons and 1 1/4" legs will be more than strong enough.


----------



## drpdrp (Oct 19, 2012)

Boy do I feel dumb. Of course I will mortise and tenon.

You see what had happened was:

I was originally thinking if I could literally just do legs and a top- then as I constructed the post and measured the goofy thing that will go under it I convinced myself that rails would fit and didn't rethink it.

As to cost… Because I am poor everything I make is out of construction grade pine. The extra couple feet of stock for the legs to be solid is not a big expense.

I like the hefty look and I hate all my friends so the heaver it is the better for if I ever move! ha!


----------

