# Table Frame Analysis



## captpschar (Sep 7, 2013)

My wife has asked for an extremely solid table framed up with 4x4 timber with a 100+Lb butcher block top. I'm attempting to design a frame without any metal fixtures that could withstand a flying drop-kick. 

So far this is the only design for the table frame she's approved, so I'm putting it up here to get some more experienced woodworkers to take a look at it and give me an idea of how solid it's liable to be and whether there are some modifications I can make to make it sturdier.

Assume all joints will be tight and glued. Please take a look and comment.


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## frankp (Oct 29, 2007)

Looks like a solid design to me. Especially if you're gluing and screwing it like the picture (and your post) indicates. It's going to be incredibly heavy with 4x4 frames. You could probably get away with 2x2 but 3x3 is definitely an option.


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## 4DThinker (Mar 13, 2013)

Add a center post (just in case) and you should be good to go. Since you half-lapped the diagonals they are only half as strong, with the center the weakest point.


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## captpschar (Sep 7, 2013)

I've heard a similar range of responses from my family and friends, some say it's overbuilt, some say it's potentially underbuilt. I'm not sure which I buy. 

Additional facts that might help bring the feedback to one side:

The span of the frame is about 59.25"
It will be made of cedar.
The slim cylinders shown in the diagram represent 1/2" dowels not screws.
I will be floating the table top.
I will be adding small foot stubs under the frame to help with leveling.


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## Pop Pop (Jul 17, 2011)

I don't believe the dowels are adding anything to the sliding dovetailed tenons since there are no forces that would be acting to lift the top cross pieces up or the posts (legs) up. The butcher block top will on its own spread a significant portion of its weight to the posts (legs) and the cross pieces should be plenty to handle the rest. If anything, I think you can reduce the dimensions to something smaller as Frankp suggests to get a lighter look. Mic you are going for a massive look, I think you have it!

You may also think about moving the cross pieces up the legs a little so it is possible to sweep under the table and only have four points of contact with the floor.


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## woodnthings (Jan 24, 2009)

*It's about the bracing*

There are many ways to make the leg to frame connection rigid. Metal brackets, ruled out here... or these "trick" wooden braces

http://www.woodworkingtalk.com/f2/leg-brace-alternative-method-challenge-33352/


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## cabinetman (Jul 5, 2007)

The design as you have it appears to be more than adequate IMO. If you elevate the bottom cross stretchers would likely call for different joinery near the bottom of the legs.





















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## captpschar (Sep 7, 2013)

First, I've attached a redesign at the bottom of this post in response to the received advice, take a look. Now on to responses:



frankp said:


> It's going to be incredibly heavy with 4x4 frames. You could probably get away with 2x2 but 3x3 is definitely an option.


I'm certain I could get away with 3x3s, 2x2s is even conceivable were it not for the 7 year old yellow belt with a temper. Anyway it's moot as I ran a reduction by the wife and she's against reducing it's size. I think she'd have me make it of 6x6's if the possibility would occur to her. Let's hope it doesn't



Pop Pop said:


> I don't believe the dowels are adding anything to the sliding dovetailed tenons since there are no forces that would be acting to lift the top cross pieces up or the posts (legs) up. …. You may also think about moving the cross pieces up the legs a little so it is possible to sweep under the table and only have four points of contact with the floor.


I thought about it, you're right about the dowels. I was thinking something that now seems a bit insane in retrospect, and I've removed them from the design. As for raising the cross pieces up the legs, I thought hell and just decided to lazy my way out and glue up some blocks over each bottom joint. What do you think?



woodnthings said:


> There are many ways to make the leg to frame connection rigid. Metal brackets, ruled out here... or these "trick" wooden braces
> 
> http://www.woodworkingtalk.com/f2/leg-brace-alternative-method-challenge-33352/


Ridiculously interesting.



cabinetman said:


> The design as you have it appears to be more than adequate IMO. If you elevate the bottom cross stretchers would likely call for different joinery near the bottom of the legs.]


As you can see in the revised diagram below, I'm inclined to try to keep the joinery I've got and just glue on some feet. Thoughts?


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## Pop Pop (Jul 17, 2011)

I think the blocks are an easy solution to C-man's cogent comment about the need for different joinery if you move the cross stretchers up. You would be gluing end grain which is not very strong so, this would be a place to use the dowelling.


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## NetDoc (Aug 6, 2013)

Perhaps you can allow an inch of dovetail for the bottom pads by removing an inch off of the legs. They won't look as much as a last minute add on, but a part of the overall design.


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## MissionIsMyMission (Apr 3, 2012)

I agree with 4DThinker and frank p. A center post would make your design a "TANK" and 2 1/2" to 3" posts and cross members would be Way more than adequate to support more than a 500# load.


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## captpschar (Sep 7, 2013)

NetDoc said:


> Perhaps you can allow an inch of dovetail for the bottom pads by removing an inch off of the legs. They won't look as much as a last minute add on, but a part of the overall design.


That's interesting Doc. I was thinking about that issue myself and came up with three basic solutions: 

1. Change the joinery on the bottom cross members. 
The only type of joint I would be satisfied with strength wise sans hardware that maintains the look of the legs other than the dovetailed ends would be a hidden foxtail dovetailed tenon. I am REALLY not confident that I could execute this joint.

2. Your solution, to shorten the legs so as to expose and inch or two of dovetail on the cross member into which I could fit a dovetailed foot.
This solution is better than #1 in that I could actually execute it, and with the seam being thereby raised to a point between the bottom and top of the lower cross member it would look more 'planned'. However the seam would still be there, making us all angry, so there's solution #3.

3. Maintain the bottom joinery, but extend the legs and its dovetailed cross section down 3.5 inches, then fit a 3.5 inch dovetailed part to complete the square for that section on the leg. 
We would still have a seam in the case but it would be along the grain rather than through and it would line up with the cross member joinery and for those reasons it would be less noticeable.

What do you think of this solution? Can anyone offer another idea?


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## NetDoc (Aug 6, 2013)

I had also thought of number three, but words failed me in being able to describe it. I like that the best. You could even use a bit of contrasting wood to make people go "Hmnnnn?"


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## captpschar (Sep 7, 2013)

NetDoc said:


> You could even use a bit of contrasting wood to make people go "Hmnnnn?"


Awesome idea!


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## woodnthings (Jan 24, 2009)

*How how do you intend to make the dovetails?*

Since this design is "all about" the joinery, I'm wondering your methods and possibly a note on your experience with hand tools.
Picking this design right out of the gate would imply you are not intimidated by the joinery.... and possibly have some prior experience? :blink:


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## ThomasOSB (May 21, 2009)

In order to avoid gluing material onto the bottom after the dovetail joint, why not have a pegged mortise and tenon? It should provide plenty of strength and you don't need to worry about the glue line.


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## captpschar (Sep 7, 2013)

woodnthings said:


> Since this design is "all about" the joinery, I'm wondering your methods and possibly a note on your experience with hand tools.
> Picking this design right out of the gate would imply you are not intimidated by the joinery.... and possibly have some prior experience? :blink:


I have extensive power-tool based woodworking experience, but I plan to do this entire project from start to finish using only hand tools. I've done a number of dovetailed boxes with saw, chisel and plane, and I've developed a method that I'm confident in, enough so that these joints don't seem out of reach.

However I don't plan to jump right into this build as my hand tool background is weak. Because of the cost committment of this build and of mistakes doing it, I plan to work my way through two end tables and an entertainment center with similar but scaled down designs, to work out the kinks in my methods on a less costly scale before I attack this beast.

This is why I'm trying to settle this design in, so that I can do others to work towards it. I project this as a 12 month process at least.

Seem reasonable?


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## woodnthings (Jan 24, 2009)

*I figured that!*

Hand tools would be your choice. :yes: You should really get this book even in paperback, it's great!
The Art Of Japanese Joinery: Kiyosi Seike: 9780834815162: Amazon.com: Books

Their joinery is amazing, way beyond my abilities, but you may benefit from the photos.... good luck on this project and please post any build photos on the progress. :smile:

As an aside, your choice of tools may also benefit from the Japanese influence. When I was there 10 years ago, I walked into a little shop with a dusty collection of slicks, mortising chisels, and gouges. What a steal as the prices marked were 10 years old and the total sale made the older ladies day. Their laminated steel is remarkable for holding an edge. www.japanwoodworker.com


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## rrich (Jun 24, 2009)

I don't see anything wrong with the design. I do see a nightmare cutting the joints. A doweled through tenon would be very attractive for the cross members and very sturdy. I would stay with the 4x4 plan as with your design the 4x4 is more aesthetically pleasing than using something not square for the frame.


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## Al B Thayer (Dec 10, 2011)

I can see only one big problem. You and your wife are going to hate it if you don't elevate the bottom cross brace high enough to clean under and around it. I don't see much advantage to using the dove tail on the lower cross brace. A wedged tenon would be better for the application and stronger. 

Al

Friends don't let friends use stamped metal tools sold at clothing stores.


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## woodnthings (Jan 24, 2009)

*agreed*



Al B Thayer said:


> I can see only one big problem. You and your wife are going to hate it if you don't elevate the bottom cross brace high enough to clean under and around it.
> Al


There may be another issue. It's difficult enough having 4 contact points/legs to mate to a floor which may be be "uneven". The design as proposed,would have long surfaces which will slide easier and if there is a small bump anywhere in the floor you will be chasing the table around. Small pads, or as suggested raise the stretchers up several inches would be better. 

You seem to have a concern with supporting the weight which is not really an issue with 4 legs. The real issue is "racking" in the corners ...IE, lateral loads, momentary or sustained as when moving it, if necessary. There are all sorts of good joinery methods that will "eliminate" racking to a great degree, mortise and tenon, through tenons, wedged tenons and of course your dovetails. 


You choice of Cedar also has some issues in my opinion. The structure of Cedar is prone to easily splitting along the length, with the grain. It would not be my wood of choice for this project, rather White Oak, or Maple. However, if this is more an exercise in joinery than building a practical table, and I can understand that, then go for it. It would make a beautiful glass topped end table, so you can see the joints..... JMO


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## GeorgeC (Jul 30, 2008)

4DThinker said:


> Add a center post (just in case) and you should be good to go. Since you half-lapped the diagonals they are only half as strong, with the center the weakest point.


No reducing of strength if joint is properly glued. Does not need center post,


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## captpschar (Sep 7, 2013)

Al B Thayer said:


> I can see only one big problem. You and your wife are going to hate it if you don't elevate the bottom cross brace high enough to clean under and around it. I don't see much advantage to using the dove tail on the lower cross brace. A wedged tenon would be better for the application and stronger.





woodnthings said:


> There may be another issue. It's difficult enough having 4 contact points/legs to mate to a floor which may be be "uneven". The design as proposed,would have long surfaces which will slide easier and if there is a small bump anywhere in the floor you will be chasing the table around. Small pads, or as suggested raise the stretchers up several inches would be better.


The feet are in the process of being designed in, definitely needed.



Al B Thayer said:


> I don't see much advantage to using the dove tail on the lower cross brace. A wedged tenon would be better for the application and stronger.





rrich said:


> A doweled through tenon would be very attractive for the cross members and very sturdy.


A wedged tenon would be much easier to execute and just as strong, granted, as would a dowel pinned tenon. The reason I am going with the huge (and difficult to cut) dovetails is because I want the joints to be on the high end of strong to resist twist and lateral stress as much as possible, while ALSO being hidden from view from the other three sides. The only joints I know of that could do this are a large and awkward dovetail or a hidden wedged tenon, and I am simply not confident I could do a hidden wedged tenon, and so would rather wrestle through the tedium of a huge dovetail.



woodnthings said:


> You choice of Cedar also has some issues in my opinion. The structure of Cedar is prone to easily splitting along the length, with the grain. It would not be my wood of choice for this project, rather White Oak, or Maple. However, if this is more an exercise in joinery than building a practical table, and I can understand that, then go for it.


Truth be told, for me it is an exercise in joinery, however in some ways it has to be one because the two design elements my wife is sticking to her guns on are:

1) That it be made of 4x4 with a 4x4 butcher block style top and be hugely imposing and overbuilt (the 4x4 top and exclusively 4x4 timbers make conventional designs like skirts impossible).

2) That it be made from cedar. I've made sure she understands that it is very soft and will get banged up quickly and often, she has requested a rough sawn like finish and wants it to look used and aged, so in a sense the softness will help achieve what she desires. As for it's proneness to splitting, I've tried to design the frame such that in order for one beam to split in a structurally meaningful way, at least one other timber would have to split to failure with it, and at least one joint would have to fail.

I may not hide under this table come the apocalypse, but after seeing some of the feedback from you more experienced woodworkers, I would go for it come a tornado.


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## 4DThinker (Mar 13, 2013)

GeorgeC said:


> No reducing of strength if joint is properly glued. Does not need center post,


With no parallel grain mated glue faces in a 90 degree half lap they tend to weaken/fail from shear after a few seasons of expansion/contraction. At that point the beams are half as strong again. I still recommend a center post, and wouldn't glue the half laps. Lag bolt through them into the post ends. Pre-drill of course. Don't over tighten.


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## Al B Thayer (Dec 10, 2011)

4DThinker said:


> With no parallel grain mated glue faces in a 90 degree half lap they tend to weaken/fail from shear after a few seasons of expansion/contraction. At that point the beams are half as strong again. I still recommend a center post, and wouldn't glue the half laps. Lag bolt through them into the post ends. Pre-drill of course. Don't over tighten.


Oh my word man! This is a piece of furniture not a pole barn. The half lap doesn't carry any weight and never will.

Al

Friends don't let friends use stamped metal tools sold at clothing stores.


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## NetDoc (Aug 6, 2013)

Al B Thayer said:


> Oh my word man! This is a piece of furniture not a pole barn. The half lap doesn't carry any weight and never will


 Al's right! The four posts will carry all the weight. The connecting pieces are only there to prevent racking. Depending on the top joints and the fact that he indicated that the top will be "massive", the upper connectors aren't really needed. Aesthetically, they are pleasing but they aren't adding much structurally.

How are you going to mount the top, captpschar???


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## 4DThinker (Mar 13, 2013)

Al B Thayer said:


> Oh my word man! This is a piece of furniture not a pole barn. The half lap doesn't carry any weight and never will.


Except it's own weight, and the weight of the top over it which it will want to deflect the cross beams as they transfer that load to the outer legs. Build that table with no cross beams or apron and it'll sag over time. Unless of course it has a center post. Might be a nice feature though, as with a dip in the middle anything spilled will tend to not run off the sides. .

You did notice how big this tables is, didn't you?


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