How long can breadboard ends be?

[Peter Aeschliman]

Long story short, I'm building an dining table for a good friend as a wedding gift out of black walnut and I'm questioning my planned use of breadboard ends. Some background first:

The wood comes from a tree his father cut down from his front yard (the house my buddy grew up in) before he passed away suddenly in an accident. He was a really good man and my buddy took it pretty hard. His dad had a portable saw mill come out to process the tree into rough stock. Unfortunately he did not properly sticker the wood and seal the end grain while letting it dry. So not surprisingly, most of the stock warped horribly. Most of it was rough cut to 4/4.

Dead set on using this walnut for sentimental reasons, I went through it, disposing of the unusable stock. It sure was painful to throw out so much but it was truly unusable. Once I milled up everything that was left, most of the stock was too thin to use for the top (1/2" or so). I only had enough left to make the top of the table, and I had to face glue pieces together to get the desired thickness.

Since the pieces I had were too short to have them run lengthwise on the top, they have to be oriented so that the grain runs perpendicular to the length of the top. Problem is, since the pieces are face-glued, the end grain is less than pretty.

That's where the breadboard ends come in- I want to use them to hide the end grain. The total size of the top (excluding extension leaves) is about 73 x 41. So each piece of the top will be 36.5" long. I want to run breadboard ends down the length of the table.

My plan is to glue the breadboard ends at the middle of the table, so that the table closes without a gap... meaning, the table will be expand/contract along its length, but out toward the end of the table only. The extension leaves will not have breadboard ends on them, so I don't have to worry about them.

So I finally get to my questions/concerns (if you've gotten this far, thanks for hanging in there):

1. Is the expansion and contraction along the length of the table going to be so severe that it will make the table look sloppy or poorly made? Said differently, how much should I expect the table to move? I don't want the breadboard ends to protrude too much, or worse yet, I don't want the center of the table to protrude out of the breadboard ends. That would look especially bad.
2. Is it unlikely that I'll be able to glue the breadboard ends on such that I get a tight seam at the middle of the table when it is closed?

Any other concerns about my design? Advice? I really want to make this table last forever. The idea is that this is something for my friend to remember his dad by, so I'm approaching the project with a great deal of respect.

Thanks!

Peter

[Cliff Polubinsky]

Peter,

Go here to the Shrinkulator and you'll be able to determine how much the wood will move. This will calculate the amount of change based on the wood species and the change in either starting and ending moisture levels or ambient humidity. With that information you'll be able to adjust your design to deal with either extreme.

Cliff

[Todd Hoppe]

Hi Peter,

Have you considered making this table expandable using slides and drop in leaves? If you did that, you would break up the length of the breadboard-ended sections into manageable pieces (e.g. 73" / 2 = 36.5" for each half, plus 12-16" width for each leaf)?

If you make the table a bit shorter, but with leaves, you could accomplish two goals: (1) you help with the expansion issue, (2) you could also add utility to the table by making it fit in more spaces, perhaps making it work for them for a longer time.

Todd

[Kent A Bathurst]

I use the shrinkulator, with some judgement applied. The extremes in RH often aren't the indicator I use - more like average monthly high and low, and use that as "worst case".

As far as your design, Peter - tee it up, I say. the difference in the length of the table and the breadboards is what you get from using real wood, as opposed to veneered plywood. Part of the charm of the deal, if you will.

Here is a 43" x 84" table top out of QSWO with breadboard ends. Not exactly your situation, but the measurement from the center to an edge is 21.5" - still not 36", but not chump change, either.

By the way - in the top photo, between the yellow bench brush and the calipers, you can see an LN face float. That tool paid for itself many times over on this table. Until you use it, you would not believe how quick, easy, and accurate it is to use. The tenon is 2" wide [deep?], and after the waste is gone, the stubs are 1-1/2" x 2" along the 1/2" continuous tenon. The float was absolutely amazing. And - because fo the design of the handle, I could run it down the inside faces of the 1/2" deep slot in the breadboard as well.


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Dec 1 033.JPG

[Peter Aeschliman]

Thanks guys.

Todd, for some reason I can't get your link to work. I googled the shrinkulator, which led me to the woodbin website... and it won't load. Maybe the site is down?

[Kent A Bathurst]

Works for me............http://woodbin.com/calcs/shrinkulator.htm

[Peter Aeschliman]

huh... yeah, the site must've been down last night because it works for me now too.

[Todd Bin]

Here is an idea. If you rout or plane a profile along the outside edge of the table top it will conceal that glue joint. You could go with something simple like a chamfer. Plane down to the glue line on a 45 degree bevel. Then sand the edge of the table to a higher grit. i.e. if you sand the top to 180 sand the edge to 320 or 400. You might be surprised at how easy that is and how much better it looks. This would also be a lot easier than the breadboards.

Also, as I understand you have the boards running perpendicular to the table length. I don't think I have ever seen bread boards on a table in that orientation. One idea I had was to use a contrasting wood like maple or white oak for the bread board. You could glue a piece to the ends of the table then apply the breadboard to the side allowing it to float. Put the glue at the middle of the table so the breadboard expands to the ends of the table.

here is a quick calculation that I did on the expansion using black walnut and holding the temperature constand at 75 degrees F and assuming the boards are flat sawn. If you start with a 36 inch wide board and the humidity goes from 20% (say in the winter) to 40% (summer) then the board would expand by 0.3 inches. That would definitely be noticible hanging past the edge of the table.

Could you post a picture or two of the table and edge?

[Kent A Bathurst]

here is a quick calculation that I did on the expansion using black walnut and holding the temperature constand at 75 degrees F and assuming the boards are flat sawn. If you start with a 36 inch wide board and the humidity goes from 20% (say in the winter) to 40% (summer) then the board would expand by 0.3 inches. That would definitely be noticible hanging past the edge of the table.

Split the difference when you cut the breadboards. You have a max range of about +1/8" to -1/8", with much of the year very near the middle - +/- 1/16". That's NBD. That's what I did on the QSWO table, but I was dealing with much less movement.

Also - Peter's in Seattle. Up there, the humidity range is what, 52% to 60%? The top will move some number of thousandths, in that case.

BTW - the idea of a chamfer is a good one. You can't hide the joint, so emphasize it a bit. I would not go anywhere near as far as "to the glue line", however. On mine, I went maybe 3/32" at most. Looks cool [says the objective observer ]. Mr. Block Plane made a few passes until the answer was "That's enough of that."

Final comment - Peter - don't overdrive your headlights on this one. It will turn out great - guaranteed. The very last thing people will notice over the decades is the seasonal movement of the table vis-a-vis the breadboard sides. Be sure to sign it and date it. And post photos when you're done, please.