# Extendable Dining Table



## anoldlady (Aug 19, 2010)

Hi folks, I have been thinking about building a dining table for a while now and have decided to just go ahead and start making the plans. I know that I want one that is extendable because we have family gatherings at my house fairly often, so I decided to go with 2 extension leaves. In its fully extended configuration, this table is a little over 12 feet long. This should easily sit 10 or more people. Tell me what you think of it. Do you think that there will be a problem with tipping? I don't know if there is a rule of thumb associated with how far apart the legs of a table should be compared to the length of the top. Perhaps you guys have some insight? I have attached the sketchup file for you to view if you want a better look.


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## GeorgeC (Jul 30, 2008)

I do not know that tipping would be a problem. (I assume that you would use both "wings" at the same time)

However I would be concerned with the forces that will be put on the mounted end of the wing. I think that much cantilever is asking for trouble. I would put legs at the end of each wing.

George


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## anoldlady (Aug 19, 2010)

GeorgeC said:


> I do not know that tipping would be a problem. (I assume that you would use both "wings" at the same time)
> 
> However I would be concerned with the forces that will be put on the mounted end of the wing. I think that much cantilever is asking for trouble. I would put legs at the end of each wing.
> 
> George


 Hi George, are you saying that it seems that the piece that is attached to the wing and that gets hooked under the edge of the table might get ripped off by putting weight on the "unsupported" end of the wing? I can see that being potentially problematic. Perhaps it would be worthwhile to make sure that it is attached using a very strong method.. Or did I misunderstand?


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## GeorgeC (Jul 30, 2008)

That is exactly what I am saying.

George


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## Steve Neul (Sep 2, 2011)

I think your leaves are too long and you could have a problem with the table tipping if someone leaned on it. The support system looks inadaquite to me as well. If you have a antique shop near you, you might go look at a drawleaf table. Each leaf has two wooden runners that extend under the top of the table which supports the leaves. The top of the table is made to float, mounted on wooden or steel pins which allow the leaves to slide under the top when not in use. That way you wouldn't have to take them off and store them somewhere.


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## Deanr (Jul 29, 2011)

Look a the thread about leaves at the end of the table. Same concept. Our table at work is about 10 feet long total with each leaf about 18 inch. It is a very heavy table made with at least 2" stock. I think that is the key to the proportions. Thicker table and keep the leaves under 2'. 

Your drawing is similar to our table except the supports are connected.

If you need measured dimensions or pictures let me know.


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## anoldlady (Aug 19, 2010)

I am not sure if it is evident in looking at the design, but there are a couple of design points that were not specifically labeled in the model:


*Leaf strength:*  The leaf supports are to be made of 1" steel tube that, when fully extended, protrude from the edge of the table 24". I was thinking that this would be strong enough to support whatever weight might be placed on it. If you feel otherwise, would you say that 1.5" or 2" would be strong enough? The skirt (or apron or whatever it is called) is 4" wide, so there is plenty of wood to support a 2" steel tube.
*Tipping: *The table top design is currently 1.5" thick (2x 3/4" plywood). I was thinking that this might be an issue and was considering ways to add more weight to the main table if necessary. I would rather not add legs to the leaves because I am working on coming up with an under-the-table storage system and doing this would require that I shorten the leaves from 36" to 29". Do you guys think that shortening them to 29" would be enough to prevent tipping? Also, do you think that this would be enough to prevent the cantilever tear-off that GeorgeC mentioned?
I appreciate everyone taking the time to provide input on this. It really helps to get other peoples' perspectives before jumping into something like this. Many thanks to all.


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## Black540i (Jan 4, 2013)

We have a table in the family that folds down to about 8in wide when not in use. It's about 6ft long when opened. It works by folding the leaves up, similar to what you have shown, and then a leg swings out to prop up the leave. It's basically a large H that is hinged to the main leg and the swings out. If that doesn't make sense, let me know and I will draw it out.


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## Deanr (Jul 29, 2011)

The 1" square tubing will be strong enough.

Is there a reason why you do not have your support tubing up against the top and leaf?

The more weight you can add to the table (especially the base) the better. Also the longer the main table is, (the farther the legs are apart) will help.


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## Bumpus (Aug 4, 2012)

It seems to me that no matter what the strength of the joinery is between the table and the leaf, the leaf extension is too long for the table. I know when I (or most people I know) get up from a table, I use the table table to aid in standing up, pressing down on the table. A habit I think that most people have with out thinking about it. Any significant downward force on the end of those extensions would cause the entire table to tilt. This is a principle I work with everyday working in the scale industry and mechcanical levers. I think that's why most tables that can be extended use the leaves in the middle of the table or shorter length leaves for the ends. Good luck with your project, I hope you work it out. Family gatherings are so much more enjoyable when eveyone can sit at the same table comfortably.


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## anoldlady (Aug 19, 2010)

Deanr said:


> The 1" square tubing will be strong enough.
> 
> Is there a reason why you do not have your support tubing up against the top and leaf?
> 
> The more weight you can add to the table (especially the base) the better. Also the longer the main table is, (the farther the legs are apart) will help.


When I first drew this up, I hadn't considered using square tubing and placing round tubing up against the bottom of the table top would require that I cut round holes in the skirt in such a way that the edge of the hole would break through the edge of the skirt. Now that you mention it, doing it this way can help to simplify the build. Do you have any ideas on how to hide the tubing when the extensions are not in use?



Bumpus said:


> It seems to me that no matter what the strength of the joinery is between the table and the leaf, the leaf extension is too long for the table. I know when I (or most people I know) get up from a table, I use the table table to aid in standing up, pressing down on the table. A habit I think that most people have with out thinking about it. Any significant downward force on the end of those extensions would cause the entire table to tilt. This is a principle I work with everyday working in the scale industry and mechcanical levers. I think that's why most tables that can be extended use the leaves in the middle of the table or shorter length leaves for the ends. Good luck with your project, I hope you work it out. Family gatherings are so much more enjoyable when eveyone can sit at the same table comfortably.


I think that I might be able to get away with leaves that are 29" long, but I do not know the physics well enough to work out the math. Do you know of a way to determine how much the main table would have to weigh to make it stable when the extensions are attached? I can add ballast to the main table if necessary.


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## Deanr (Jul 29, 2011)

Below are pictures of our table with square tubing which slides up against the underside of the table. Let me know if you need different views.


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## anoldlady (Aug 19, 2010)

Deanr said:


> Below are pictures of our table with square tubing which slides up against the underside of the table. Let me know if you need different views.


On your table, do you have a problem with the leaf wiggling or moving away from the main table? I can't see how this is prevented in your pics. Is there a mechanism that prevents this?


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## mmwood_1 (Oct 24, 2007)

You've got a 6' long table with 3' extensions on either end. Granted, pushing down on one end could cause the other end to lift, but it would take a fair amount of force to do so. Here's a suggestion. Since you are not using solid wood anyway, inquire as to whether you can get your ply with an mdf core instead. 1 1/2" thick mdf in the center would add substantial mass. Even if you used an mdf core with a different species of veneer for the bottom layer(if it's unavailable in the wood you're using), it would still add mass to the center section.


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## Deanr (Jul 29, 2011)

It's actually pretty simple but effective how the leaf is held in. If you can see on the picture the support is connected with a cross piece. Also note the little white round plastic piece at the end of the wooden rails on the underside of the leaf.

To install the leaf you slide the protruding end of the rails under the main table while holding the leaf at an angle. (first the tubing support is fully pulled out) Then let the leaf down and the square tubing is immediately outside the two wooden ruuners. Set the leaf down and the cross piece of the runner rests on the two white circles and is held by the end of the runners. The runners have a bevel to them on the end.

This set up makes for an extremly strong and stable support. Granted the leaves are not the length you propose.


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## anoldlady (Aug 19, 2010)

mmwood_1 said:


> You've got a 6' long table with 3' extensions on either end. Granted, pushing down on one end could cause the other end to lift, but it would take a fair amount of force to do so. Here's a suggestion. Since you are not using solid wood anyway, inquire as to whether you can get your ply with an mdf core instead. 1 1/2" thick mdf in the center would add substantial mass. Even if you used an mdf core with a different species of veneer for the bottom layer(if it's unavailable in the wood you're using), it would still add mass to the center section.


I have never used MDF before. How well does it hold screws and glue compared to plywood? If I used it for all but the top layer of the tabletop, would I run the risk of stuff coming apart when someone lifted the table by the top? From what I have seen of it, it seems kind of crumbly.


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## Deanr (Jul 29, 2011)

I realize my previous pictures weren't the best.
Here's a few more.


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## mmwood_1 (Oct 24, 2007)

anoldlady said:


> I have never used MDF before. How well does it hold screws and glue compared to plywood? If I used it for all but the top layer of the tabletop, would I run the risk of stuff coming apart when someone lifted the table by the top? From what I have seen of it, it seems kind of crumbly.


All materials have their pros and cons. I seldom use mdf core because it is my belief that ply will hold screws better. But, if you used coarse thread screws, and a length that was about 3/4 of the thickness of your material, you would likely be okay. My thought was that if you just use it for the center section, the main table, you would add a significant amount of weight/mass to it. Use ply for the extensions to keep them a little lighter. 

I have seen screws pull out of mdf, but it takes a fair amount of torque. Myself, I go with solid wood for table tops. They take abuse if you actually use them, and solid wood can be repaired more readily than veneer.

Here's a question for you, though: what happens to the extensions when they're not in use? They can't just hang down like a drop-leaf because they are too long. Do you pull them out and store them somewhere? That would leave the holes in the apron visible to the world.


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## anoldlady (Aug 19, 2010)

mmwood_1 said:


> All materials have their pros and cons. I seldom use mdf core because it is my belief that ply will hold screws better. But, if you used coarse thread screws, and a length that was about 3/4 of the thickness of your material, you would likely be okay. My thought was that if you just use it for the center section, the main table, you would add a significant amount of weight/mass to it. Use ply for the extensions to keep them a little lighter.
> 
> I have seen screws pull out of mdf, but it takes a fair amount of torque. Myself, I go with solid wood for table tops. They take abuse if you actually use them, and solid wood can be repaired more readily than veneer.
> 
> Here's a question for you, though: what happens to the extensions when they're not in use? They can't just hang down like a drop-leaf because they are too long. Do you pull them out and store them somewhere? That would leave the holes in the apron visible to the world.


You can see in the 1st picture that when the extension supports are retracted, the wedge-shaped end caps are the only part of the support system that are visible. I tried to make them look somewhat decorative. Perhaps, it would be better to put a decorative carving on them to distract the viewer from their real purpose.

The 2nd picture illustrates how the angled connected to the bottom of the table mates with the angled part of the end cap and the weight of the extension pushes the extension tight against the main table.

As for storing the extensions: I am currently working on devising a storage system for them that will allow me to store them under the tabletop. I have some ideas, but nothing has proven ideal yet.


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