# Extending Dining Table - Timber Selection (page 3)



## OPJ

Hi guys,

Good news is, I have been asked to make dining tables for two different people!  In both cases, they will need to extend from four-seaters to six-seater tables. There, drop-leaves are out of the equation as they'd only get in the way of four chairs.

Some kind of extending or 'expanding butterfly' table is what I'm after, where the top slides apart two central sections unfold from below. Trouble is, while I can see how this works and have even found a great design for doing most of this in wood and brass, I'm having trouble getting the proportions right and would appreciate some feedback and advice here.

One of these tables will be my competition entry, by the way. :wink:

Okay. While I've drawn these out with square ends, it's quite possibly the final design will be move oval-shaped or elliptical... Perhaps I should draw that out first? I'm sure the shape will have some effect on the dimensions of the frame work... :?







Please ignore the design of the legs and rails for now; it's the top we're most interested in. I've stated off with 100mm overhang at each end.






Looking at the second photo, I'm thinking that 350mm overhang is too much? Most sources recommend 600mm as an ideal spacing for one person. I've drawn the central sections at 500mm to try and reduce some of the overhang but, it hasn't made much of a difference...

For what it's worth, the second table I have to make will be slightly shorter than this one in its length. Any thoughts on setting this out correctly would be much appreciated - sadly, that information is lacking in the otherwise excellent I found. :roll:

Also, (DaveR? :wink I'm looking for guides or walkthroughs on drawing ellipses in SketchUp.

Thanks for reading,

Olly.


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## OPJ

Right. I've figured out how to draw the ellipse - drawing a Circle and using the Shift tool (S) to elongate it.  It's not exactly what I'm looking for; too oval-shaped... 

So, instead, I've drawn two circles to give me curved ends, which looks more appropriate. This does require so re-working of the frame so, bear with me...


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## p111dom

Might have something to help you out there Olly. I'm at work till 10 but will post a pic of something in the morning.


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## SketchUp Guru

Ellipses? The Shift key?

To draw an ellipse, draw a circle first. Then select it and get the Scale tool. Hold Ctrl (option on Mac) to invoke Scale about Center while you pull/push a scale handle in the center of one of the sides of the bounding box.

If you only need part of an ellipse, you might like the shape you get from a 2 degree Bezier curve instead.


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## MickCheese

The overhang of 350 looks quite a lot to cantilever off the frame.

How much is inside the rail? Is it 200 less the width of the rail?

With someone leaning on the extended top at each end would your hardware be beefy enough to hold?

Mick


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## p111dom

Sorry OPJ can't find them at the moment to take a picture, I must have put them in the loft but it's a metal table mechanism so when you pull out one side the other extends. It's a salvaged item but it really good condition. Its not the best quality but works well, would be hidden anyway and runs off wires and pulleys rather than rack and pinion. There's one for each side. Any use to you?


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## OPJ

DaveR, thanks for the tip, although I figured it out not long after my original post...  

Mick, sorry, I don't understand your first question...

In response to your second though, here's a drawing which illustrates the 'dovetailed bearers/runners' that I would like to use. At the other end (on the inside) will be a brass plate to prevent them from sliding two far so, the top can't come off the end of the frame with the plates attached. Elongated holes will allow the top to expand and contract.






(Please ignore the UFOs in the background!! )

I was looking at some other extending tables on Google last night and they all seem to overhang by a fair amount. :shock:

Dom, your mechanism sounds interesting. Thanks for the offer, it does sound interesting but, I'm in favour of working with as much wood as possible on this one. I'm sure someone else is building a similar table for the competition - perhaps they'd be interested?


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## xy mosian

Hi Opj,

The mid 20th. century 'Utility' furniture had a draw leaf table in which the top was the center portion. This stayed in place as either one, or both, leaves were pulled outwards into place. These leaves were mounted on wooden runners which formed cantilevers under the centre section when in use. Over extension was prevented by metal pegs to limit the movement. Any weight applied to the leaves was transmitted to the large centre section giving a stable top surface.

I cannot imagine how this approach could work with a non-rectangular top, but it is essentially all wood and fairly robust in use. 

xy


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## OPJ

Xy, this idea sounds very intriguing - do you have any links or photographs to illustrate further? I've tried searching the 'net (Google) but, as you would expect, I'm generally coming up with all the imported 'catalogue' furniture! :?

One of these tables will be rectangular, it has been confirmed. It would be nice to attempt two _different_ mechanisms for each of the two tables, if they're appropriate.


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## OPJ

Hang on, just found this! :roll:


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## SketchUp Guru

Ah yes, the draw leaf table. Seems like I good option.


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## OPJ

I'll see now what I can come up with in SketchUp. I think this draw-leaf option will work well with the smaller table, which is 1m long x 750mm, extending to 1500mm in length. Thankfully, both ends will be square as well. I've tried setting this one out in the butterfly style but, there isn't enough room between the legs for the central section and a decent length of runners.

Splayed legs are out of the question as we've already agreed on 70mm square with no tapering. Looking at this diagram, the leaves, top and centre board look only 19mm thick - is there any reason I can't keep them at 32mm :?: Maybe I should be looking for 1¼" stock and a 25mm top? :?


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## xy mosian

Hi,

Thank goodness you found the image. I cannot think how to sketch that. Now I have one of these tables, it always amazes those who come across it for the first time. 

The top is 1060mm, closed, with two leaves of 300mm each. making a 'full' top of 1660mm. Width is 760mm. 

If I can figure out how to take a useful 'photo I'll do that but in the mean time the drawing you found is spot on. By the way the ends on my table are curved, not greatly, but enough to add character.

xy


p.s.
Ok! figured it out. I could not relate to the 'Top will rock' bit. On the table I have there is no centre board, which will allow the rocking movement. The gap between the leaves, in the closed positon, is filled by a batten fixed to the underside of the top on each edge. When a leaf is extended the top is therefore able to drop to be supported on the table frame. Right so the top is lower, or if at one end sloping slightly, but in 20 years I've never found a problem with this.

xy


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## OPJ

If you are able to take and upload some photos Xy, that would be much appreciated.  I think I've got the gist of how the drawing works although, I'm still struggling a little with the slides/runners...






I've drawn them 19mm thick at the narrow end, also assuming they would need to increase by the top thickness (32mm) at the wider end.

I can see how the leaves slide out in to position but, not how the raise up so they are flush with the top. I think I may need to add a partial taper (not full-length) to the top edge of the slides, so they clear the centre section :?:

It probably would've been easier to draw the final position first and add the notches from there...


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## Steve Maskery

Olly
The top will be 38mm thick when closed, because there are two layers, one on top of the other. And even when open, the centre section will still be 38mm. It's only the pull-out ends that will be 19mm.

The leaves have to rise by 19mm to ensure that they are level with the (main) top when they are extended. So the taper must be 19mm over the length of the pull-out. As the leaf is withdrawn, the main top is lifted up and up, until the leaf is fully extended, when the top drops back down the 19mm so that it sits flat on the runners again.

The problem with all extending-leaf tables, it seems to me, is that when extended, 4 people have a table leg in the way of their own. My dining table is built in two halves, so that the whole leg assemblies separate and the center is filled with a butterfly.No-one has a leg in the way. But it is rather heavier to operate, needs two people really, and you can't do it after the cloth has been laid, whereas you can pull out an end-leaf if grandad pops round just as you are sitting down to Sunday Lunch.


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## xy mosian

Olly,

Ok! First thing is SWIMBO says Thanks!. The bit of carpet under the dining table has been vac'd for the first time since christmas, well not really but in some time anyway.

I've taken some photos, hope they help.

Table with 'centre top' removed and one leaf partly open.





Table frame with whole top removed to show woodwork. The guide rail structure is screwed together.





Underside of leaf, note offset runners.





Underside of leaf taken from side to show shape of runners. Note the knocks in the runners to prevent over extention. Of course when you look at a familiar object closly you remeber things about it. The top does not drop as the leaf is extended, the leaf runners are shaped to lift the leaf as it passes over the table end rail.





Underside of top with leaves closed. You can clearly see the overhang from the table frame. Note the metal fittings to prevent the top sliding and the rails to the side to close the gap between the leaves when seen from the edge.





Underside of top with one leaf fully extended.






I tried to take 'photos which would give me all the information I would need to produce a table like this, but may well have forgotten something. If you would like larger images or more information let me know. 

You will have noticed, certainly SWIMBO has reminded me, that this table is part way through restoration. I must admit it has been for some time.

xy


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## OPJ

Xy, those photos are brilliant - thanks for taking the time and effort to get them uploaded for me.  Thanks also to Steve for clearing things up. I was also looking for a design where the frame slides apart. But, as you suggest, it would require two people and I think that would be a problem for my client anyway.

Xy, I can also understand and see now what you were referring to with the battens and, how the 'gap' between the two leaves is hidden by a pair of rails; in effect, creating a 'hollow' panel. 

I'd still like to get these runners sorted though...






The lower of the two in the drawing above is what I originally had in mind, which I now believe is incorrect. So, should I be looking at something like the top runner, where it is effectively tapered on both top and bottom edges? Except, on the top edge, the taper starts after the flat which is fixed to the leaf... Hopefully, the guidelines I've left in will help to illustrate what I'm trying to say :? :wink:

Whatever I do, I think that I'll end up making a softwood and MDF mock-up of this before getting the oak out!


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## Steve Maskery

OPJ
This post is edited to remove total twaddle.
S


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## OPJ

Okay, thanks Steve.   In that case, I need to make the slots deeper in the stretcher rail to accommodate the widest part of the taper. Of course, it won't tilt in its resting 'position' because it's sat on top of the rails! But, once extended the tapers will sit in the notches, holding it in place - I think I get it now! Cheers.


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## SketchUp Guru

Isn't it nice to be able to work all this out in SketchUp rather than hacking away at real wood?


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## OPJ

Exactly!  Not only do you save timber and money but, it's so much easier than drawing out a full-size rod on a sheet of MDF. Of course, there are times when you _need_ to work from a rod and SketchUp cannot help you there. But, I do prefer to use SU for the initial design stages.


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## Steve Maskery

OPJ":3mgtjso6 said:


> In that case, I need to make the slots deeper in the stretcher rail to accommodate the widest part of the taper.



Are you sure about that? I'd cut a few pieces of cardboard out, cross-section of what's going on, if I were you.



OPJ":3mgtjso6 said:


> I think I get it now!



Are you sure about that, too?  'Cos I don't think you have, quite yet. You're getting there though, the penny is about to drop.
S


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## OPJ

Alright, Steve, I admit I still haven't quite got it yet... Part of the problem is I'm trying to do three drawings at once - and, for some reason, I find myself trying to use the Orbit function on the UKW forums...  

Let's go back a couple of steps...



Steve Maskery":2qg0kbgd said:


> The leaves have to rise by 19mm to ensure that they are level with the (main) top when they are extended. So the taper must be 19mm over the length of the pull-out. As the leaf is withdrawn, the main top is lifted up and up, until the leaf is fully extended, when the top drops back down the 19mm so that it sits flat on the runners again.



Okay. 19mm thick boards giving 38mm with the centre board. Each leaf needs to rise by 19mm so, if my runners are 19mm thick at the narrow end, they should 38mm at the other right :?:
However I've worked this out, they are slightly thicker... :?

I'm also trying to simulate the physical movement of an individual leaf in SU, which isn't easy. From what I can tell though, the leaf and runners remain parallel up until the point at which the leaf is clear of the top, at which point it should rise up to be flush.

Obviously, the rails keep things parallel... :-k I still don't see how the runners can rise enough to keep the leaf parallel, without fouling the centre board.... Hang on. pipper! I've drawn the tapers wrong, haven't I - they shouldn't be flush against the underside of the centre board!! :roll:


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## Steve Maskery

For goodness sake, Olly, just give me a phone call tomorrow! 

Edit - More Twaddle Removal has been done here.

Make a 1:5 mockup.

And give me a ring or you'll be here 'til Christmas.

Edit - And maybe that way you can help me get it straight, too. And to think, I had one of these many, many years ago.
S


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## xy mosian

Ok!. 

The top surface of the runners, attached to the leaves, is parallel to the top surface of the table. 

The slot in the table frame, to take the runners, is deep enough that the leaf, in the closed position, is resting on the frame. 

When the leaf is fully extended the depth of the runner is such that the upper surface of the leaf is flush with the upper surface of the table top. While the top remains in its original position with relation to the frame, and the floor. The top is relatively free to move vertically to allow withdrawal of the leaves.

Take a look at the image I posted of the leaf taken from an angle. Careful study will give an idea of the runner shape. I do not think that the curve is strictly necessary. 

xy.

p.s.

The long grain runner is sliding across the grain at the bottom of the slot in the rail. A slippery insert here could make the action more silky, perhaps a piece of Formica, or similar, or even a hardwood plug.

xy


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## OPJ

Damn! I just typed a reply but, obviously didn't hit 'Submit' - that's how well things are going for me right now!! :x

Thanks again for your replies, guys. My apologies for my short-sightedness...



xy mosian":6ctdanzy said:


> The top surface of the runners, attached to the leaves, is parallel to the top surface of the table.



Is it parallel along the whole of its length? I only ask because, in the photos, it looks (to me, anyway!) as though it's only parallel to a point, at which it tapers off. Or, the rail is set and an angle and the short taper is parallel with the the top leaves. Could be an illusion.

Thanks for the tip on Formica, I will give that a try.

I'm gonna have to start cutting some cardboard and gluing bits of softwood together soon. My 'shop is full of beech and my heads too full of c**p right now though. Steve, I'll probably give you a call some time next week when I've got the mock-ups on the go - that should give you some time to get the paracetamols ready!!


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## Steve Maskery

Olly, it's the taper bit that's parallel 

That is, the tapered part at the end, to which the leaf is attached, is parallel with the top of the table (ie it's level). That means that the main direction of the rails is very slight down wards towards the centre of the table, like a very flat V.

The angle of that V is determined by the thickness and length of the leaf.

I think I'm not talking ******** today.

S


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## xy mosian

Yup!.

Top surface of runner(s) is parallel with the top surface of the table for its full length.

Any variation on thickness takes place on the underside, nearest the floor, in use.

xy


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## Steve Maskery

xy mosian":25c8nste said:


> Top surface of runner(s) is parallel with the top surface of the table for its full length.
> 
> y



Er, surely not? If the leaf is to be levl, and it's on a tapered section, then the rest of the rail must be very slightly downward? Or am I having another Senior day?

One of us is going to have to draw this up.
S


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## OPJ

Steve Maskery":2zqtropk said:


> One of us is going to have to draw this up.



Trust me; I've been there and it doesn't get you anywhere!!  :wink:

I'm glad you asked the question though because I was feeling puzzled once again! Don't know why I didn't think of this before but I consulted Joyce's "Bible" earlier and it is as you last described, with the taper running parallel to the top and the bearers set on a slope.

I'm feeling a lot better about this now, so, thanks guys.


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## OPJ

There is one more question I have, regarding the draw-leaf design...

Obviously, the grain of the top and leaves is running across the width of the top, rather than it's length. I assume the positioning of the travel stops is critical so, how do you allow for expansion and contraction?

I've now sent a quote for this job and I'm waiting to hear back. I'm also hoping I've persuaded her to go with brown oak, which means I can clear out some of the narrow offcuts I've got piled up at college! :wink:


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## Steve Maskery

Olly
The travel stops are not that critical. If you allow an extra inch, that will be more than adequate. You pull the leaf out, the top drops back into place, you push the leaf in. It's not going to go anywhere.
S


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## OPJ

With the basic design out of the way then, I'd now appreciate some feedback on timer selection. She's sent me two photo's of her existing floor and she wants the table to match this as close as reasonably possible:

One with a flash:







One without:






I'll admit I'm trying to push the idea of brown oak, simply because I have bits and pieces left over! (I'd still need to buy some more for the top and legs). This is something I've been making at college, with a coat of Danish Oil on:






As far as ordinary English Oak goes, this is the best photo I can find. Again, it was finished with Danish Oil, even though it looks very light:






She admits that the quality of her photos aren't excellent (neither are mine!) but, her floor is apparently somewhere between the two; perhaps closer to the one with the flash.

Her first reaction was that my cabriole legs are too dark, while I don't think the rails are that far off...

Any thoughts, anyone? She would like to see some lighter options but, I'm concerned English oak will be _too light_ and I really want to avoid staining if I can help it! :?


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## xy mosian

Hi,

Thankfully, Wood is Wood. Unless you use a gloss colour from Dulux, or anyone else, the colour will change with the direction the light is falling on it. That is the beauty of the stuff. 


French polishers used to apply finishes in the final resting place of the piece. Of course I don't recommend that route. But any finish you apply will likely change in shade over time anyway. I have seen the shade of a wooden table change through the applied finish, think of sunlight fading a table top, except where the Aspidestra was. 

Best of luck getting some agreement.


xy


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## MikeG.

The only way to match Olly is to go and visit with a whole lot of samples. These will have been finished with a whole lot of different finishes, inc. dyes and waxes, oils, lacquers, even varnishes etc. Lay them down on the surface you are matching so that they catch the same light in the same way, and make a judgement. 

When you are choosing, you have to allow for it darkening over time.........so it is pretty much guesswork anyway, unless you keep a library of samples for years and years.

Mike


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## OPJ

Okay, thanks guys. I knew you were going to say something like that, Mike! :roll: 

I think my best bet would be to buy a Trial Pack of spirit stains from Axminster (something I should've done with the Blanket Chest...). Staining English Oak looks like the best way to go. I've got a few scraps in the workshop and there are plenty of bits of brown oak at college, if needed. My shopping list at Axminster is quickly building up now! :?

I'll also oil some bits of oak, just in case. Ironically, this table is actually for Pete's mother - must be something about the 'Soft Moose' clan and staining...!  :wink:


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