# Expanding Circular Dining Table



## George Johnson (19 Aug 2015)

Hi,

I have just finished this expanding circular dining table. I have wanted to make one for a while and finally found a client who wanted to commission one. The top is veneered in walnut curl, I think this is one of my favourite woods.
Working out the mechanism took a while and quite a few prototypes, but as always, the next one will be a lot quicker!

There is a video of me operating it on YouTube here https://www.youtube.com/watch?v=FooHhYwNjXs

George


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## marcros (19 Aug 2015)

wow. just wow.


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## Adam9453 (19 Aug 2015)

Absolutely stunning, I'm sure the mechanism is as difficult as could possibly be


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## n0legs (19 Aug 2015)

Very very cool =D> =D> 
Welcome aboard.


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## dzj (20 Aug 2015)

That's a very nice looking table. Well done.
The glossy finish wouldn't be my first choice, but to each his own.
Mdf substrate for table top?

Some of the older expanding tables have no mechanism at all. 
The inserts are connected manually and it takes a minute or two, but it's not a big deal
since guests don't come around every day (thankfully).


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## George Johnson (20 Aug 2015)

Hi,

I agree with the gloss finish, but it's what was wanted. Although it always seems to look more extreme when taking photographs! 

All the sheet materials I used were birch ply to be a bit more rigid than MDF, next time I might use 25mm thick boards instead of 18mm for even more strength.

I like the old expanding tables, like the Jupe mechanism, but I wanted to make a table where the expansion leaves were stored within the body of the table and not kept separately.

George.


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## Mike.S (20 Aug 2015)

Beautiful =D>


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## Sheffield Tony (20 Aug 2015)

George Johnson":2l4t9sxl said:


> I like the old expanding tables, like the Jupe mechanism, but I wanted to make a table where the expansion leaves were stored within the body of the table and not kept separately.
> 
> George.



It is a truly magnificent table. 

Now you just need to figure out a design with stowage space for the extra 4 chairs :lol: :lol:


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## Parquet Dave (20 Aug 2015)

A true work of art, absolutely outstanding.


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## JR147 (20 Aug 2015)

Wow, that is stunning


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## mailee (20 Aug 2015)

That is just fantastic George. Do you have any details of the mechanism, I would love to make one of those.


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## George Johnson (20 Aug 2015)

mailee":185yi6q1 said:


> That is just fantastic George. Do you have any details of the mechanism, I would love to make one of those.



Hi,
I will have a go at explaining it!!
In the last photo you can see a little inside the table before it is fully assembled. 






The central section with the three ramps visible stays still, the outer ring with the 6 table top segments attached rotates, the table top pieces move on ball bearing runners and are attached to the central stationary section with metal rods so that as the outer ring moves around they are either pulled in or pushed out. From closed to open the table moves through just less than 120 degrees. The expansion leaves are not in this photo, but they are in one piece, and sit on small castors with their weight in the centre of the table. They are rotated by engaging with the small blocks visible at the front of the picture. As they move round the castors run up the ramps raising the expansion leaves up to the level of the rest of the top, then they can be unfolded.

I hope that makes sense!

George


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## Harbo (20 Aug 2015)

Fantastic just fantastic!
Nice chairs too.

What finish did you use?

Rod


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## George Johnson (22 Aug 2015)

Hi Rod, 
Thanks! I used Liberon Finishing Oil after putting a grain filler on. I think I must have put about 15 coats on in the end! 
George


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## RogerM (22 Aug 2015)

George Johnson":2jt5k1ke said:


> mailee":2jt5k1ke said:
> 
> 
> > That is just fantastic George. Do you have any details of the mechanism, I would love to make one of those.
> ...



Thanks George. That is Mega Impressive. Is the expansion mechanism anything like the one *described here?*


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## George Johnson (22 Aug 2015)

Hi Roger,
There are some similarities, but quite a few differences! The segments move out radially using the same iris principle, and ramps are used to lift bits up. But his table has an extra level of complexity as you don't have to go around unfolding the expansion leaves, and the mechanism to raise the central star is really ingenuous! It's great that there are so many ways of making these tables, each probably have different advantages depending on the size of the table and how much you want it to expand...... It's got me thinking again for the next one!!
George.


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## RogerM (22 Aug 2015)

Thanks George. I'm just aching to try and build one of these for ages, but regretably we don't have a suitable space for an expanded table.

There's also *this one*, but I think your solution is far more elegant.


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## beganasatree (22 Aug 2015)

Thanks for sharing it is absolutely stunning,well done.


Peter.


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## Biliphuster (23 Aug 2015)

Amazing work, very nice mechanism and wrapped in beautiful veneer to boot.


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## Woodmonkey (23 Aug 2015)

Great work George, just had a look at your website, there's some lovely stuff on there. You must have some wealthy clients!


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## Tonytygwyn (23 Aug 2015)

I have to agree WOW


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## RogerM (23 Aug 2015)

George Johnson":2w02fkjw said:


> Hi Roger,
> There are some similarities, but quite a few differences! The segments move out radially using the same iris principle, and ramps are used to lift bits up. But his table has an extra level of complexity as you don't have to go around unfolding the expansion leaves, and the mechanism to raise the central star is really ingenuous! It's great that there are so many ways of making these tables, each probably have different advantages depending on the size of the table and how much you want it to expand...... *It's got me thinking again for the next one!!*
> George.



Yep - me too !  Looking carefully at your interpretation, you get away with one fewer tier on your design than Scot Rumschlag does on his, and with considerably fewer moving parts, so I should imagine less to wear out, less friction in operation, and I suspect easier to get each segment to register accurately with the adjoining one. 

Looking at each of the "pie" segments, they appear to be located high above the runners, and also when fully extended, they overhang the skirt well past their centres of gravity. How are they attached to the runners, and how do you stop the table edge sagging under it's own weight as I can see no attachment close to the sharp end of each segment?

Sorry for all the questions, but I'm a sucker for wanting to understand how things work!


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## George Johnson (23 Aug 2015)

Hi Roger,

I have attached a photo of the table as I was building the mechanism so you can see how the top segments are attached.







The metal runners and ball bearing blocks come as a set. (two rails and 4 blocks) I made the steel brackets that bolt onto them and then attach to the segments. The top segments are also just in contact with the skirting all around the table so they have support from there as well. All the pieces join together with tongue and groove joints, so once the top is locked together everything is nice and solid.

Hope that makes sense!

George


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## RogerM (23 Aug 2015)

Perfect sense thanks George. Many thanks for sharing.


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## RogerM (24 Aug 2015)

George Johnson":3nalda8k said:


> The metal runners and ball bearing blocks come as a set. (two rails and 4 blocks) I made the steel brackets that bolt onto them and then attach to the segments. The top segments are also just in contact with the skirting all around the table so they have support from there as well. All the pieces join together with tongue and groove joints, so once the top is locked together everything is nice and solid.
> 
> Hope that makes sense!
> 
> George



So on each rail there are 2 blocks set in close proximity? Presumably there is some integral locking mechanism (other than gravity) that holds the block down on to each rail so that each segment doesn't overbalance when unsupported during expansion? Those don't look like standard under mounted drawer runners, so presumably designed for some other purpose - not specifically for expanding tables?

edit - Presumably *something like this* or *this*?


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## George Johnson (24 Aug 2015)

Yes, the second link, except I used 350mm long rails. They are really good, when the four blocks are bolted together there is zero lateral movement, and they move along the rail with virtually no resistance!


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## pcb1962 (24 Aug 2015)

Woodmonkey":26u4tysf said:


> Great work George, just had a look at your website, there's some lovely stuff on there.



+1
I spent a good half hour looking at your portfolio at the weekend, phenomenal.


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## cusimar9 (27 Aug 2015)

Superb, well done sir!


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## nicguthrie (28 Aug 2015)

Just utterly gorgeous.

A great blend of art, woodwork and engineering.

Thanks for sharing.

Sent from my SM-N9005 using Tapatalk


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## Bluekingfisher (4 Sep 2015)

This will be around for a couple of hundred years for people to enjoy and appreciate.

Incredible craftsman ship.

David


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## pembles13 (16 Oct 2017)

Hi George,

I am trying to make one of these as they look fantastic! I am trying to sketch it all out before I start cutting (could get expensive quickly otherwise) and I'm a bit stuck on how you achieved the profile of the rods that push the 'pies' outwards when you rotate it? How did you calculate them, or was it trial and error?

Thanks, and again, it really does look amazing. Sadly I'm not such a veneer wizard as you so mine will look a little more plain I suspect.

Olly


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## MusicMan (16 Oct 2017)

I am speechless with admiration.


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## fezman (16 Oct 2017)

That is absolutely beautiful, never seen one before either


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## Ian down london way (17 Oct 2017)

Truly marvellous - I'm in awe at your execution. 
I'm trying to make a much smaller version (a coffee table), using plans from mechanical lumber web site. just started this week.


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## angelboy (22 Oct 2017)

Truly amazing! I'm in awe at your skills!

How much could a buy a table like that for?


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