Mounting a slab to a base. Help wanted.

A couple of years ago, I acquired a lovely slab at the Timber and Working with Wood show. I have finally got my act together as far a flattening it, and have made some headway towards its final finish (it is intended to become a coffee table). On instructions from the keeper of the Treasury, I purchased at last year's show a very nice stump that is intended to become the base of the table. My problem now is that I need advice as to the best way to fasten the two together. I intend to cut the stump down, as it is too tall for my purpose at present. My intention is to have the two pieces joined without any additional pieces or brackets, etc. or at least none that will show when the item is finished. Ideas, please?

Mike.

Mike,

How thick is the slab and what is the diameter of the top (or will it be) of the stump.

Then we'll know what we've got to work with.

Without knowing the dims. You could cut a disc the size of the pedestal top then slice that up to create a keyway for a dovetail key.
Attache the keyway pieces to the underside of the tabletop.

create the other half of the dovetail key into the top of the pedestal
Make the key to fit - then lock them together.

Extending this you put in laterals as well to make a four way key to firmly affix the top to the base. Not sure if the image helps or makes it harder to understand.
Attachment 249064

An idea to start with anyway

Hi Mike,

You could glue in a couple of loose tenons between the slab and the stump. Fat ones would be better. Or you could make a mounting plate or frame that sits between the underside of the slab and the stump to hide all the mechanical bonding nastiness. Sort of like a stylish 2" thick box or something. The sort of idea used in pendant light fittings to hide the connections on the ceiling.

The only issue will be the amount of strain the will be placed on what ever jointing system you use, especially if heavy objects are placed on the edges of the table or people lean on it (common with little kids or older people who are a bit err, "tired and emotional" after they've had one too many cool beverages while watching the cricket...:rolleyes: ) or it gets carried around by the top. This is where some sort of underside support or brackets will give extra strength.

The timber looks nice and don't forget more pics please.

Cheers


Bryan

Quote:

---

Originally Posted by dr4g0nfly

Mike,

How thick is the slab and what is the diameter of the top (or will it be) of the stump.

Then we'll know what we've got to work with.

---

The slab is approx 40mm thick, and the diameter of the top of the stump approx 180mm.

Mike

Thanks, enelef and Tung tied. Both of your ideas have got me thinking. I do have concerns with lifting the table to move it about, as the base will be very heavy, and lifting will necessarily be done by the slab top. As you point out, there will be a significant amount of stress on whatever joint I use. I am now contemplating maybe using a disc of steel, perhaps 300mm diam, fixed to the top of the stump with large, long screws, and then screwed from the other direction into the underside of the slab, using a spread of shorter screws spaced around the circumference. If I use steel of 1/4 inch thickness it would not be visible from any normal perspective, as the table will be no more than 450mm high. Those who are very tired and emotional may be able to view the underside fixings, but hopefully will be unable to bring the steel parts into focus.

btw, enelef, your drawing was perfectly clear, and easy to understand. I envy your Sketch-up skills.

Regards, Mike.