I am designing an island table with a 2″x21″x60″ top. I want to use wedged thru tennons for joining table legs into the top. I also want to use rails and stretchers just below the table top to help support the top. I intend to use mortise and tennon joinery into the legs there also.
My question is: Am I going to have a problem with wood movement with the top and the legs held so rigidly with the rails and stretchers just below it?
I am thinking the top will not have any attachment to the rails and stretcher…just kind of float on them.
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Replies
Yes, if the top is 2" thick solid wood it will try to separate your legs in summer and pull them together in winter. If you live someplace with little seasonal temperature and humidity swings you could be ok. If you live in the NE United States it will destroy itself.
I would suggest a standard connection to the apron. If you wanted to you could add decorative false through tenons and if you keep your mouth shut you'll be the only one who ever knows.
ya i was afraid that would be the answer. I live in the SE...just as bad as the NE, maybe worse.
Thanks for the response.
Ha ha - honest joinery becomes dishonest. :-) It's an interesting theme with furniture, in all seriousness.
One strand of the Arts & Crafts style of furniture is "honesty" - the truth of how a joint or other feature of construction is exposed to sight rather than hidden under some decorative veneers, moulding or other concealment of the joinery and materials actually used. Exposed through tenons of the wedged kind were one main feature of such A & C honest joinery, as were butterfly-joined table top planks and exposed dovetails.
But as the style became fashionable and eventually "a classic" the features of A & C honest joinery became desirable motifs in furniture that was not actually constructed with through wedged tenons, butterfly lock joiners or other common A & C joinery features. They became dishonest fashionable features added on as surface veneers or insets.
Just little white lies like so many in stuff manufactured to be fashionable, one might say. No harm done. And perhaps this is so.
But little white lies can become grey, sometimes dark grey. As that same A & C "movement" of early times noted, much Victorian era stuff made to sell purely for profit and therefore made to look fashionable (coated in the apparent motifs of good furniture design-styles) became so internally degraded in substance and construction that it was unfit for purpose.
In modern times a huge amount of stuff advertised and sold to us as fashionable is dishonest to the point of being a big grey lie. Much furniture could be labelled as FSO - Furniture-Shaped-Objects. They look like a piece of furniture but the quality of materials and the mode of construction are very poor albeit overlaid with some fashionable presentation. Before much use the dowels pop out of the chipboard, the plastic veneer cracks off and the whole thing sags because the humidity changed 10%. The off-gassing of the chipboard glues gives you a headache every night.
****
Of course, the OP is wanting honest through M&Ts. An advisor is right to suggest their use as the OP suggests will result in the table cracking, in all likelihood .... but that a pretend through M&T can be used as " ...if you keep your mouth shut you'll be the only one who ever knows". This is true; and the table top held on with buttons pr whatever will be a better design. The addition of some dishonest M&Ts won't degrade it.
But dishonest joinery is perhaps the crest of a slippery slope. It leads to the precipice over which one goes to make MDF stuff thrown with a few screws or dowels that is not only inexpensive and easy to make but also dysfunctional. ..........
Or so says the "philosophy" of Arts & Crafts. :-)
Alternative opinions would be interesting. mind.
Lataxe
PS
Getting carried away with A & C woffle, me. .....
Should the OP want to attach the top to the undercarriage of the table with through and wedged M&Ts, it would be possible to do so by adding an additional central rail running between the centres of the two short aprons, into which the wedged through M&Ts could go. You could have a line of them down the centre of the table top let into that under-rail.
Any expansion of the top would be no problem as it can expand & contract back & forth with the middle being the only line of attachment of top to undercarriage. The only disadvantage is that an already heavy table becomes monolithic as you can't take the top off....
....Although you could still make it all knock-down if the top and rail can be disengaged from the short aprons via something like a bed bolt pair with the bolt heads recessed in the short aprons and covered with a nice dangler of some kind. The bed bolts would go into the under-rail ends.
Knock-down parts would be: two of short aprons with two legs; two long aprons; one top with it's M&T'd-in under-rail. The under-rail could be an arch -shape, with meat at the ends for attachment to the short aprons but just thick enough in the middle to take the through wedged tenons.
Just a thought.
Lataxe
Another design thought.
Suppose the top of the legs were tenoned and let into through mortises going into the table top, as the OP desires. Any expansion and contraction of the top across it's width would be a problem because the long grain of the short rails wouldn't expand and contract at the same rate as the cross grain of the tabletop. So ....
Make the short aprons of cross grain too (grain running up & down across the apron width rather than side-to-side along the apron length). But this would make the short aprons rather weak. So ...
Reinforce the short aprons with a long grain or plywood backer strip on the inside, attached with small bolts that can slide in short slots. The short aprons would then be glued to the legs at each end (long grain to long grain joint). The remaining weak point would be where the short aprons meet the legs and there can be no backer board reinforcement because an expansion-contraction gap must be left between the backer board and the legs. So .....
Put in corner blocks that attach to the inside ends of the long aprons and to the backer board of the short aprons, with the latter attachment also via a small bolt in a slot, so it can allow movement with moisture changes.
Feel free to pick holes in this design.
Lataxe
Whatever's hardest.
I agree with Lataxe's philosophy regarding disingenuous fabrication techniques. I am a professional designer and it seriously goes against my grain to put "decoration" above authenticity. But, that's just my personal feeling and if someone doesn't mind the deception, it's their right to go down that road.
A few points-
You are rightly worried about wood movement of the table top. What wood are you using? Beech moves a lot with humidity changes, but mesquite moves very little. Check on how much your wood species will move and design accordingly. Also consider your top has only 21" of cross grain. Your legs will likely be inside that width so even less cross grain will causing movement problems.
Also I wonder why one needs additional rails and stretchers to help support a 2" thick, 21" deep table top. It seems to me that size and thickness has plenty of strength on its own and the through tenons would provide good support for the legs. If you like the look of the stretchers and rails, which I do, why not let the tenons of the cross grain rails float in the leg mortises? You could attach those rails to the top in the center. Then glue the rail tenons that are parallel to the grain. If you build the table now (summer, high humidity) leave a little room in the tenon cheeks for table top shrinkage. If you're building in the winter fit them tight.
You say this is an island. Will it have a lower shelf? If so, that shelf with its supporting rails would provide support for the legs against side pressure.
You can do it exactly as you described but the rails need to be allowed to expand and contract with the seasonal movements of the wood. I would do it exactly as described, the rails held to the underside of the tabletop with cleats but each rail is actually two pieces end to end with a gap between In the Center to allow for the wood contraction, They could be joined by a floating tenon glued to one end of the rail and allowed to slide in the other mating half. The gap needs attention to look like a design feature.
Jkatzowitz... Deception? Seriously? Who would be decieved? Is a veneered panel with wood edges to hide the substrate deception? How is sturdy construction, however decorated, less than authentic?
That's a pretty high horse you're riding 'pard.
Gulfstar, you just reminded me of a build 20 years ago for a site-built expanding table. At the time I called it the handshake joint.
Put your palms together and slide your hands up the sleeve of the other arm and you'll have the idea. 2 identical parts with long tenons sliding into opposing boxes. Might work here for the OP. Thanks for the ticket to memory lane!
Yep, that is what I was trying to describe. There are dozens of ways to skin that cat, sliding dovetail etc.... One could imagine a high quality black rubber joint between the two ends of the rail that would look like a strip of ebony inlay but allow for very small movements of the wood top.
jfsksa and Gulfstar, I like both your ideas.
The wood being used is some heartpine from a home built in the 1860s. the wood has been kiln dried. My shop is climate controlled and the home it is going to live in also climate controlled. While those facts don't mean the wood won't expand and contract, it might be minimized.
I did think of letting the tennons in the cross aprons float...but I also like the idea of the expansion allowed in the center of the cross aprons.
Would I really need to attach the top to these cross aprons? they will only be about 10" long. I could use some dowels made of holly...about 3" long, 2 for each cross apron, 1" into each piece with a 1" gap between the apron pcs. I like that idea quite a bit actually. There would not be any gap appearing at the tennon shoulders at the legs, and by my reckoning, I would not need to worry about more than an 1/8"-3/16" movement anyway.
Thanks Folks for the advice...love it.
_MJ_,
You ask: "Deception? Seriously? Who would be deceived? Is a veneered panel with wood edges to hide the substrate deception? How is sturdy construction, however decorated, less than authentic"?
A veneer is, by definition, a means to pretend that a thing is made of what the veneer portrays whilst hiding the substrate. In that sense, the veneered furniture is inauthentic. Of course, it's a well-known deception and so no real deception at all, especially if the underlying construction is still a piece of well-functioning furniture. But it depends what else the veneer hides besides just the different appearance of the substrate.
Much C18th century veneered furniture had the veneer on a perfectly sound substrate (less expensive and perhaps easier to work wood) with perfectly sound joinery. Well .... mostly.
In the late C19th much of the veneered stuff was not just hiding a different appearance but a substandard interior of poor material badly joined. In the late C20th and early C21st the veneers often hide stuff that's basically junk. (Destined for the landfill in the near future). In fact the veneers themselves are often junk in that the appearance is reduced to a poor photo-print of a nice grained timber on a piece of easily degraded plastic, badly stuck on some inadequate plywood or chipboard not really fit to last longer than the next fashion cycle.
So, there's deception and then there's deception. On the other hand, anyone who doesn't realise by now that cheap modern furniture is just a lot of FSOs (Furniture Shaped Objects) might be regarded as one of those suckers that shouldn't ever be given an even break.
Lataxe
Attaching the rail to the top will allow the tenon in the leg to provide adequate force against the bending forces applied when the table is pushed sideways. cleats (called buttons in the article) , wood or metal are quite easy to install, they require a slot in the rail and are screwed on the underside of the top.
https://www.finewoodworking.com/media/TabletopsFlat.pdf
_MJ_ I was referring to your comment "you could add decorative false through tenons". How is that not deception? In any case, if you read my entire post you'd see that I also said "it's their right to go down that road". I'm not judging anyone, I was just stating my personal opinion on authentic design.
Deception derives from a dishonest intent. Building something to achieve a desired look is not dishonest. Now, if he was building for a client and had promised wedged through tenons your point lands.
Is the use of squared plugs to cover screw holes "deception"? What about a false front on a drawer? The concept of "authentic" is ridiculous in this context.
The use of terms like "disingenuous fabrication" and "decoration above authenticity" (whatever that means) seems judgemental to me.
The concept of "authentic" may seem ridiculous to you but it's not me. In fact it's how I try to live my life. So please feel free to live yours however you like.
Happily the OP has got lots of cogent advice about how to achieve not just the look he wants but authentic means to achieve it rather than just a means to achieve an appearance suggesting that his piece is made in a way that it isn't. So that's the main theme of the thread a success, eh?
***
It's my fault for going on about the notion of honest joinery that another theme of the thread has emerged concerning authenticity.
_MJ_,
I feel you know very well what "disingenuous fabrication" and "decoration above authenticity" mean. These aspects are a feature of an enormous amount of modern manufactured goods of every type. In woodworking, for example, we're all familiar with the history of late C20th "tools" that are only TSO - tool-shaped-objects - that look like they're planes or chisels but can't be made to function as such to any acceptable degree. They're made badly, at low cost, without care to function but rather to sell at a low price to dafties duped into thinking they've got a bargain.
You can find things of this kind if you dig in any landfill. I fact, you don't have to dig as the whole surface is littered with such manufactured dross.
I recall my first years as a wage earner and how I was duped along with the rest of the masses by "goods" that weren't good. I bought inexpensive (relatively speaking) "furniture" from a large precursor of IKEA that was utter rubbish. It was made of that plastic-veneered wood print over crumbly chipboard that didn't survive a drag across the floor, a damp bit of weather or opening and closing a door more than twice a week.
You can find this "triumph of image over substance" stuff everywhere you look, including furniture stores. It's made to become obsolescent in short order, to feed the money-generating machine of the fashion cycle and the bottom-line-is-everything notion.
Part of the wood working tradition promoted, encouraged and enabled by FWW magazine has always been the attempt to retain or re-introduce the authentic - in what's produced, in ways of working and in the tools used. This doesn't exclude the authentic hiding of one sort of material and joinery under another, as in the veneering traditions. Nor does it exclude decorative considerations as any sort of antithesis to good construction and design.
But I think it does exclude the sort of dishonesty and inauthenticity that is rife in so much mass production of furniture; and everything else. I suspect that a number of other hobby woodworkers will have had one motive for becoming such similar to my own, which arose when my daughter told me that she was about to make the same buying mistake I made myself when first starting work. .....
She wanted a bookcase to house all her university books in her first unfurnished apartment. She was going to spend £80 (a third of her monthly wage) on a flat pack chipboard thing. I told her I could build a far better one for a quarter of the price; and I did. That was my start in woodworking - although it cost me rather more than the £20 for wood and glue since it was the beginning of the tool-acquisition thing.
And guess what? I made the same error in early tool buying of giving good if (relatively) small amounts of money for a Record plane that wouldn't and some generic Big Store chisels that didn't.
Inauthenticity is everywhere in the form of goods shaped and painted to look like something .... but aren't.
Lataxe
great discussion fellas. I appreciate all of it and empathize with all of it as well.
I used to own a cabinet shop in the 80s...the beginning of the cabinet factory mania. the cabinets looked good but were made with 1/4" casework that were hot melt glued together. the only thing real about it were the solid wood face frames. I spent more time in my shop rebuilding these 'cabinets' than it took to install them.
I made a point at that time to never fall into the trap of 'cheap to build and sell but looks good'. Those factories were soon forced to upgrade their designs...although they have never really achieved the classic handmade look or quality. Today they sell for high dollars too.
So, i am still of the opinion that authentic, craftsmanship, and attention to detail in design and function are the highest standards we can achieve.
Jkatz: I said the concept of authentic IN THIS CONTEXT is ridiculous. The context being a handmade object for one's own use. That you took my words out of context to toss out a rather personal judgement is par for the course I suppose.
Lataxe; Yes, I understand the terms but there is nothing inauthentic in the making of anything, only in the misrepresentation of that thing. Is a newcomer to the craft working to his / her skill level to be frowned upon?
A router cut dovetail, a domino'd joint, and a pocket screw are all authentic. Stanley's line of inferior tools under the Sweetheart badge to take advantage of an old reputation is disingenuous fabrication.
How can we apply these terms to a man making a table to his own standards for his own use?
_MJ_,
The OP wants to make a set of authentic through wedged tenon style of leg-tops let into a matching set of authentic mortises in his table top. I believe his question was about how to make these joints as the real-deal items rather than to produce just a decorative effect. He was concerned less about making the through tenons than about how the use of such a joint would affect the rest of the construction in terms of possible wood movement and consequent splitting of the top if the legs were also attached to the shorter long grain aprons.
You initially suggested this: "If you wanted to you could add decorative false through tenons and if you keep your mouth shut you'll be the only one who ever knows".
This is unequivocally a suggestion to make not just a decorative effect but a dishonest claim that the joinery of the table top to legs was wedged through tenons when it wasn't.
As you say, plenty of people would be happy to make a table like that and plenty would be happy to have a table like that. But however much we accept this, the technique is less about having a decorative effect than it is about pretending that a certain kind of joinery was used when it wasn't. Otherwise what is your "....keep your mouth shut you'll be the only one who ever knows" about?
Your later suggestion of a handshake joint to allow the wedged tenons to be used without issue seems a response more suited to the OP's intent. He thought so.
*******
Its a slippery slope from real to faux. Portrayal of a certain kind of high class joinery that doesn't actually exist whilst hiding that fact is surely a perfect example of the inauthentic; and in a commercial context, dishonesty. (Not relevant in this case, I know)
But why would any maker of a thing for himself try to be dishonest with himself about the joinery he used by using a faux image of a joint instead of actually making it?
Lataxe
Is there a need for another thread to discuss the notion of honest & dishonest joinery; use of faux overlays; decorative vs functional styles; and so forth? Oh, I do hope so! :-)
Lataxe
Lataxe,
The original Q was if movement would be an issue with the suggested joinery, the answer was yes. My suggestion regarding keeping your mouth shut was a nod to our compulsion as craftsmen to point things out rather than simply accept a compliment. I was offering a way to get both the desired stability and the desired look. Perhaps I could have been clearer on that.
The idea of being dishonest with yourself is interesting... The cutting and fitting of the wedged through-stubs would offer almost the same exercise in the making.
Actually, there was a way to get the required joinery and make the construction sound.
Yup, downside to posting first thoughts. I enjoyed the process though.
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