Dining Room Table Design HELP?!?

[adowden]

I am currently trying to design a George Nakashima inspired walnut slab dining room table. My biggest concern is that I know I would like a Frenchman's Cove II base design, but I cannot find dimensions anywhere. I have found lots of pictures and have done my best estimating scale, but with a project this important the less variables the better. So my main question is, "Does anyone know where I can get dimensions for this base?" My second questions is ,"Does anyone know the joinery that Nakashima used in his cove tables?" The legs extend beyond the base on both sides, but I can't tell if he remove material from both pieces to equalize the modified tenons. My last question has to do with the table top. I am using two large walnut slabs and attaching them with butterfly inlays. I want to attach the top to the base with wood buttons and screws. The FWW article I found ran a routed slot along almost the entire inside of the table support for the buttons. I would rather make individual slots for each button with a little extra wiggle room. Does anyone see a problem with doing it like that? I'm just thinking it would look a little "cleaner" from the underside.

Here is a link to a table similar to what I want to build.

http://www.1stdibs.com/furniture_item_detail.php?id=125144

Thanks for the help,
Amy

 

[SRhody]

My two cents: can't help on the dimenions, do a cardboard mock up or scaled drawing to get the scale you want. It appears from the link that a Bridle Joint was used primarily to connect the feet/base and cross members. On attaching the base/legs to the top, recommend your approach with oblong screw slots (to allow for seasonal expansion) covered by appropriate wooden buttons/plugs.

 

[cpowell]

Amy,

I have used a tape measure or calipers and a calculator to determine sizes for pieces like your table. For instance, if I liked the table proportions in your link, I'd print out a hardcopy of "View 2" and then use the supplied dimensions to determine the scale and just go from there. It's not an exact science but has always gotten me VERY close.

Once you determine dimensions you like you can sketch a scaled drawing using graph paper (engineering paper?), CAD or whatever and see if you like the proportions.

Your top attachment sounds fine.

That looks like an interesting project. WIP pics would be pretty cool!


Chuck

 

[Dutchman]

Amy,
Here is a quick sketch to get you started. His base looked a little a little to short to me, so I stretched it a little. I scaled it assuming you are using his 72 x 40 x 29"ht. I bumped up his 28 ½ht. to 29". I would suggest you notch the posts and the cross members for strenght. I agree with your plan to do a series of routes for your top attachment screws as opposed to one long route. I would suggest using a pan head screw with a washer to allow for movement. Those must be a couple of pretty nice walnut slabs you have. Good luck.

 

[adowden]

Thank so much for the help. The sketch is very similar to what I drew up today (but much neater). The actual dimensions of this table will be around 36" wide by 29" high and around 96" long. The customers want to keep the natural shape of the slabs around the outside. They actually bought the slaps from someone in Western NC last year (they are pretty).

The one difference between my sketch and Buddy's is that I made the thickness of all members 1 3/4 figuring that I could get that out of 8/4 stock. Will that be O.K. or should I buy 12/4 instead?

The one thing I still can't visualize is the joinery. The material on the outside looks so thin. Based on Buddy's sketch, I'm imagining that if the legs are 3" that some material is chopped out of the base support to allow the visible parts to be thicker than you can see. Something like one inch thickness on all parts. Am I making this way too complicated?

Thanks again for the help. This is an exciting and overwhelming project!

Amy

 

[Travis Porter]

That is going to be a complex but very awesome project!

To me, the joinery looks like you may be able to do pinned bridle joints or something similar.

Do keep us updated on your progress!!!

 

[Dutchman]

Amy,
I think you can get by with 8/4 for the horizontal members, but for the posts, I think it would look to light. You might have to glue up two pcs for the posts if 12/4 is hard to get.
One other suggestion, is to use a bridge plate. The bridge plate would be a nice piece of plywood under the the top. Set it in to the edge of you cross members at the top and add a nice 3/4 x 3/4 cove moulding to hide the plywood edge. Use t-nuts in the top of the plywood and run bots up thru your top cross members and bolt them into the plywood bridge plate. I would bore & counter bore for the screws to attach the bridge plate to the top oversize so the slabs can expand and contract. The bridge plate will allow the top to be easily removed (delivery) and provide a good surface for the top to sit on. Its not what George did, but it will make the table more practical, especially since its for a cutomer who will probably have trouble running and removing screws for top attachment. The bridge plate will also allow you to tie the base together better at the top. If you are not sure how a bridge plate works, go to a furniture store and look at a pedestal dining table. They all use bridge plates.
As for the post notching, you need to notch both the post and the cross members to ensure a tight fit and not make the post to weak.

 

[DavidF]

I share your concerns about the dims on the bridle joints Amy. There could be some tremendous racking forces on those lower ones where the posts straddle the cross feet. To keep the cheeks light weight for appearence you could have a full depth tenon into the cross feet with the cheeks on either side. You could have a 1" thick tenon and two 1/2" cheeks. Glue and pin the joint.

 

[adowden]

Thanks everyone for the help. I am understanding alot more about this project. Today I made a sample bridal joint out of foam. The pieces interlock both with the leg cradling the foot and the foot is recessed to accept the top 3/4" of the entire leg to help with racking forces. I'm going to try to attach a picture here.

Here is a picture of the joint when assembled.

I went yesterday and bought 12/4 walnut stock for the base. This is going to be a fun project!:-D

Amy

 

[DavidF]

Amy, that looks like a good compromize between having just the cheeks and the full central tenon, although I wouold prefer the tenon! The additional long grain glueing area on the sides you have now will help considerably. Have fun with it!

 

[johnpipe108]

Thanks everyone for the help. I am understanding alot more about this project. Today I made a sample bridal joint out of foam. The pieces interlock both with the leg cradling the foot and the foot is recessed to accept the top 3/4" of the entire leg to help with racking forces. I'm going to try to attach a picture here.
<snip>

That's a great development and analysis technique! :icon_thum

I often use whatever I have available around the shop, such as scraps of MDF, and I used a similar "mock up" technique with that material when trying out the joinery for a first-time attempt at a musical instrument, using built-up construction, before committing a good piece of wood.

I wish I had thought of something similar on some of my other projects, especially as I'm still quite a novice at joinery. It's very good to see these ideas of imaginatively using various, sometimes unothodox, materials to help work out the job details!

 

[adowden]

I picked up the slabs today and signed the contract. Here is a picture of the slabs.

They are incredibly flat and good and dry. Now the work begins!

Amy

 

[DaveO]

Wow Amy that looks like fun. I wish someone would pay me to play around with some big wood like that. I have always wanted to make a slab table, but just don't have the need for one in the house, and the materials are a little too expensive to build on spec.
Please keep us posted of your progress, this is going to be a awesome table.
Dave