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Discussion Starter #1
Hello.

I have been shopping for a new dining table to comfortably fit 6 people, but I'm not liking anything I see. So, I've decided to build a base to support a solid slab of granite or marble as the table top.

Ideally, I'm thinking of building two pillars to set the table on and was wondering if there were any other folks that have designed a wood base that is strong enough to support the weight of a roughly 80''x40'' piece of granite/marble.

I saw this type of table top at a granite store, but the base was a granite box leaving very little leg room.

Any thoughts?
 

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I don't like the idea of just 2 posts for support = too much stress along a single line.
Unless each post has some heavy duty wings above knee height.

Based on the area and the weight of the granite, etc., slab pieces that I have,
this could be 800lbs or there abouts.
 

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I was thinking about crossing some steel plates in the shape of an 'X' across the top of each post for support...but I sure don't want to mess with building something that is the least bit unsteady for such weight.

Will the safest design be the "granite box" that I referenced in the original post. That will make it even heavier!

Thanks for your advice :thumbsup:
 

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Sawdust Creator
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Sure it's possible. Good joinery is important here. This isn't a spot for pocket hole joinery. Do you have a picture of the look of the base your going for?
 

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Sawdust Creator
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Wood is plenty strong for this application so long as it's designed right..
 

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The weight is a concern, but the real problem is the amount of overhang (support is needed to prevent cracking...). Steel is a good idea, however it will add considerable weight. Wood could easily support the weight if designed and constructed properly. Something else I would be thinking about is the table will likely be very top heavy and may need to be fastened securely especially in earthquake country, or other issues that could possibly cause it to tip which could be very dangerous.
 

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I don't like the idea of just 2 posts for support = too much stress along a single line.
Unless each post has some heavy duty wings above knee height.

Based on the area and the weight of the granite, etc., slab pieces that I have,
this could be 800lbs or there abouts.
800 pounds is really not that much weight. You are writing about supporting this weight mostly in compression. One 4x4 can easily handle the weight.

The problem is that you do not want the granite (marble is not good for this application) to have much overhang. It is easily subject to cracking/breaking.

I would build a frame that provides support to within 3 or 4 inches all around. Talk to one of your local granite suppliers for the actual unsupported dimensions allowed. You could make a very nice hard wood support structure.

George
 

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Ok....that wasn't the look I was picturing. No problem at all with building two big boxes to support the weight...but I agree...talk to the granite guys about the overhang. I was picturing a less modern, more timber frame style leg system with two 6x6 posts as the main columns.
 

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Do you intend on using granite that is 7cm thick like the picture. If so you will be dealing with way more weight than 800 lbs. The weight will vary depending on the stone You select but it will be nowhere near 800 lbs.

If you are going to use 2cm or 3cm, which is the most common thickness for counter tops, then you must take support of the top seriously. The base will have to be FLAT. The amount of deflection that the granite can take is almost nil. The base design will also have to be able to withstand putting the top on it. These slabs can not be carried flat. It will break under its own weight. It will have to be carried vertically then rested on the side of the table about in the middle of the width of the piece. Then in a fluid motion, rolled over to meet the support and then slid into place. This will be a significant amount of force to a structure not attached to the floor or wall.

Engineered stone may be a better product for this application, if you like the way that it looks.


Good luck.
 

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I don't know what equip you have. If you had a full shop with a lathe there are much more elegant pedestals. This thing can be built with a power miter and a 4 inch palm sander.
 

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Sawdust Creator
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I think something similar to the above picture was what I had in mind.... I don't think turned posts would match the feel of granite. I'd go square and angular.
 
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