5'x5' table top

[phil harold]

She Who Must Be Obeyed, requested A 5x5 dinning table
going to make the top out of cherry Air dryed 5 -7 years
Turned legs and aprons painted white

how much expansion will I have
bread boards?

how to keep this top flat and fastened to the base

all info is good
thanks

[Stephen Cherry]

That's an interesting dimension- minimum size for 8 friendly people. Just that dimension invites the consideration of veneer on a sheet of baltic birch.

[Jamie Buxton]

The answer to the expansion question depends upon where you live. For instance, Boston sees bigger humidity swings than San Francisco.

[phil harold]

That's an interesting dimension- minimum size for 8 friendly people. Just that dimension invites the consideration of veneer on a sheet of baltic birch.
That was the idea 8 people
solid wood it will be


The answer to the expansion question depends upon where you live. For instance, Boston sees bigger humidity swings than San Francisco.

South Dakota humid and hot in the summer
ultra dry in the winter

[Sam Murdoch]

It will certainly expand and contract seasonally but bread boards are only warranted if you don't want to see the end grain.
Build an apron that will support it within 8" to 10" of the edge and attach with wooden shop made table top attachments or the
metal version. Here are a few options - http://eberhardt.bz/GME_Wood_Land/GME_Woodworking_Stuff/0_Techniques_Information/Joinery/7_Tabletop_Attachment_Joint.pdf

And some metal type connectors - http://www.rockler.com/product.cfm?page=784&site=ROCKLER

Here is some info about wood movement and breadboard ends - http://www.thewoodwhisperer.com/articles/do-they-know-about-shrinkage/

I built a 60" wide single plank mahogany table top in the 80s - and I think 60" is wide - with it's own apron that allowed the table top to be removed from the base with the apron still attached to the table top. This was a great system. The "apron" and the separate trestle table base were attached to the table top using wooden turn buttons but the top was never unsupported around the perimeter because of the separate apron. That table is still proudly in use today and pretty darn flat. Wish I had photos but I think they are not available. Will need to look on our old computers in the "grave yard".

[Art Mann]

I have used the calculator at the link below and it seems to be fairly accurate.

http://www.woodbin.com/calcs/shrinkulator.htm

[Jamie Buxton]

Using numbers from Bruce Hoadley (Understanding Wood), assuming flat-sawn cherry, I get about 7/8" shrinkage in the 60", going from air-dry outside in the humid summer (12% EMC) to house-dry inside in the winter (6% EMC). You can cut the shrinkage in half by using quartersawn boards.

I like Sam's suggestion: no breadboards. The aprons will keep the flat top, and not make the shrinkage obvious.

[Mel Fulks]

I'm sure you can make it work ,especially considering air conditioning is pretty standard these days, but kiln dried stuff would be my choice for 60 inch width. I would use slightly sprung joints.

[phil harold]

I'm sure you can make it work ,especially considering air conditioning is pretty standard these days, but kiln dried stuff would be my choice for 60 inch width. I would use slightly sprung joints.
Why do you assume That it will be air-conditioned for its life?
Furniture should be made to withstand the ages, you can not count on air-conditioning and heat for the life of the table
I hear guitar builders say the same thing, instruments need to be built and kept in environmentally controlled conditions
I guess Stradivarius never was told that...

[John TenEyck]

I'd agree with the comment that using breadboards ends will just lead to grief, whether or not you attach them "correctly". You can't stop the wood from moving if the humidity changes and the expansion/contraction of the top will be huge, as noted already. It'll look good about twice a year for a few weeks, and ugly the rest of the time with the breadboards ends either too long or too short depending upon what the humidity was when you built it. Personally, I'd use shop sawn veneer on BB plywood, as someone suggested, especially if you have your heart set on breadboard ends. That will stay flat if you veneer both sides and won't expand/contract all over the place. 1/16" or 1/8" shop sawn veneer looks, feels, and wears just like the real wood that it is. You can even make the ends look like end grain if you want. I made these table leaves about 4 years ago with an MDF core, but they look just like the solid core/veneered top.

269850269851



John

[Howard Acheson]

Using the Shrinkulator, the estimated range of movement using a guess at your range of humidity during the year, your tabletop will expand/contract about 0.6" to 1.1". You can make your own estimate by going to the Shrinkulator at http://www.woodbin.com/calcs/shrinkulator.htm.

With that range of movement, your table would not be a good candidate for a breadboard edge. That much mismatch between the table and the breadboard would not be very attractive IMO.

[Mel Fulks]

It would have to shrink a lot more than that to get into my house.

[Stephen Cherry]

solid wood it will be



I've built plenty of tables around 36-42 wide, but never anything 60. That said, here is what I would consider. First, I would go with thicker aprons, at least one inch finished thickness, preferably 1 1/4 or more, preferably Quarter sawn material so that the aprons themselves are not moving around as much. I would glue and screw a cleat on the inside of the apron with elongated slots to attatch the top with screws with washers, normal hole in the middle. This will allow the apron tho keep the top flat with some authority. Also, I would consider two cross peices between the long grain aprons to keep the top held flat in the middle of the table, with similar slots to attatch the top.

One thing I have noticed is that in the old days, tables were built with a lot more structure in the aprons than what is typical today. Maybe they understood better how to keep wood flat with big changes in humidity.

[John TenEyck]

OK, here's an idea if you just gotta use solid wood and breadboard ends. Make it shrink in the middle! Make two 2-1/2 ft wide pieces and join them together with your breadboard ends, but pin them only at the ends of the breadboards and let them float at the center. Same thing for your aprons underneath; pin them only at the ends, or even just one end. A sliding dovetail works great for this application, BTW. You could use a spline (unglued or glued only to one half) between the two pieces of the top to keep them in registration and to prevent the gap from showing when they shrink. At this time of year you should be able to build the top tight at the middle, but check the MC to make sure. Next Winter when the top dries out the outer ends will still fit perfectly with the ends of the breadboards - the shrinkage will result in the center joint growing wider.

John

[phil harold]

breadboards are out...


tanks

[Jim Neeley]

Phil,

You won't want to pass this on to SWMBO'd but there is a way to successfully use breadboard ends although She may not like the look.

The key in incorporating that much movement is to incorporate small fractions of it in a number of locations. To that end you'd utilize perhaps10 boards 6" wide with ship-lap joints between then and a tongue-groove between the board end and the breadboard end. You pin one spot on each board, on each end, and accomodate small amounts of (0.06 to 0.11) movement in each joint. If you didn't like that you could use 20 boards 3" and allow for 0.03 to 0.055" per joint. Its not as easy as a single board and it might be prone to catching on things or leaking liquids if spilled but I've used the technique on the back of a 5' wide x 8' tall cabinet where the back was to be of solid wood.

I only posted this for your info on future projects; if you've sold her on "no breadboards", I'd stop there! <g>