Breadboard End With Mitered Corners

[Ken Krawford]

I'm helping a friend make a table with a breadboard end. He would like corners of the breadboard be mitered. The table will be 43" wide.

This is what I have in mind but don't know if it will work. Any feedback would be appreciated.

302990

[jack forsberg]

i would only put the miters on the beadboard so the table can dry without spliting

[Kent A Bathurst]

Danger, Will Robinson!!

I am assuming that there is solid wood in that diagram, not veneered plywood.

You have not seen any furniture built this way. For a reason.

This design will fail dramatically. The table body wil contract and expand. You cannot stop that. The breadboard end will not move in that direction, period. So - the best you can do is plan a gap at the 45 that will allow for closure at minimum dimension, and then allow for max gap in months of higher humidity.

Anything along these general lines has to be built as a frame-and-panel, with the panel free-floating inside the 4 frame components.

You can do exactly what you want to do with ply and veneer, but in that case you have no use for the breadboard ends at all - you could just appy the veneer to give that appearance.

[Charlie Velasquez]

i would only put the miters on the beadboard so the table can dry without spliting+1 . . . Otherwise I would be worried about the field of the table making a mess of the miter joint as it expands and contracts. Better to go with a traditional design?

Or as Jack suggested, incorporate a mitered return in the breadboard itself....

edit.. I see Kent beat me to it. Listen to the words of hundreds of years of craftsmen doing this.

[keith micinski]

The main body of the table isn't really going to expand very much but it will contract a whole bunch and then close that corner up and destroy something.

[Randy Red Bemont]

I agree with everyone else on this. That 43" top will move enough and with breadboard ends like that it will self-destruct. I like Jack's idea to miter with returns on the breadboard only so the top can move freely. Same look but better approach.

Red

[Peter Quinn]

If you're friend wants mitered corners, you do a mitered frame and treat the field as a panel, preferably a veneered plywood panel, because even with a 6" frame thats still a 32" wide panel, lots of potential movement. If you're friend wants breadboard ends, you do bread board ends, its a great way to keep thin tops from curling, looks good too...but the field must be allowed to float in the slot in the ends. What you have drawn is the recipe for failure on a top of that scale. Don't do it. If you understand the wood movement...and it really does move....its quite clear thats a problem.

[Kent A Bathurst]

The main body of the table isn't really going to expand very much but it will contract a whole bunch and then close that corner up and destroy something.

Not picking an argument, but follow the logic here:

It is winter. Assume this all get rolling in early Feb - coldest, driest part of the year in much - or all - of lower 48. The lumber has been sitting in the shop long enough to be fully acclimatized.

The lumber is now "pre-shrunk" if you will. Build the table. THere is no more shrinkage left to take place - it will only expand. THen, of course, shrink back to current state, but no more than that.

[keith micinski]

Not picking an argument, but follow the logic here:

It is winter. Assume this all get rolling in early Feb - coldest, driest part of the year in much - or all - of lower 48. The lumber has been sitting in the shop long enough to be fully acclimatized.

The lumber is now "pre-shrunk" if you will. Build the table. THere is no more shrinkage left to take place - it will only expand. THen, of course, shrink back to current state, but no more than that.

I built this table in February under the same assumption also. I have had this happen twice now I might add.

http://www.sawmillcreek.org/showthread.php?212304-Breadboard-end-extreme-movement&highlight=

Also check out the wood whisperers not so rustic outdoor table. Same thing happened to him. I don't have anything other then my experience but For me no matter when I build it I expect to experience more shrinkage then expansion from the start of the project. I had to end up removing those bread board ends and trimming them down so that it was a more reasonable gap. I left it just a little proud because it was spring and like you thought well in the middle of summer it's going to expand a little more and this wil be my happy medium. Wrong, it didn't expand at all and it gets pretty humid here.

[Prashun Patel]

Yup. It happened to me too, Keith. It happened on quartersawn white oak on a 24" wide table.

[Peter Quinn]

Wood shrinks when it looses moisture, period. So if your wood is shrinking always, it must be less than dry going into the project. In my area in dead of winter RH is generally high teens to low twenties, and once acclimated my KD hard woods generally fall around 6.3-8% moisture on a reliable meter. Come summer time RH goes up in my area to around 50-70% average, wood moves to around 8-10.5% moisture. And it always grows. Some more than others. I used to be involved with flooring manufacture, heard many a story about building shelled in summer, dried in in fall, trimmed in winter.....floors shrink and gap right into the spring. Hey...shouldn't they expand? Not if they went in wet.

so I guess the assumption that your wood will grow in spring is
based on the assumption that it is dry now and acclimated to its environment, which is also dry now as is the normal situation for much of
this country in winter. If your situation varies your results may vary too.

[Ken Krawford]

Thanks everyone for your input. You confirmed what I was afraid of. I never thought about putting a return on each end of the breadboard to eliminate and end grain showing. That's what I'll do.

[Charlie Velasquez]

I don't know if you are out of the woods, yet. I have made a number of mitered picture frames, but I think the widest stock was 3". I am not sure what width you are talking about, but there might still be some movement that must be considered in your design. I know when I made a wide 6" stretcher for my bench I had to use double mortises to account for movement

Maybe it is small enough that the type of glue could account for it. Or, possibly a pegged splined miter with elongated holes (I kinda like the picture of that... Contrasting pegs could be a nice detail) but I would have no idea which direction the elongation should go... Don't even know if such a joint exist.....

Maybe someone with experience in mitering that width can give some insight.

[Kent A Bathurst]

...... if your wood is shrinking always, it must be less than dry going into the project.

^^^^^
This.

I intentionally put in the caveat: "The lumber has been sitting in the shop long enough to be fully acclimatized."

Otherwise, this becomes my Dad's anecdote about walking to school through snow, 2 miles to school and 2 miles home, uphill both ways: "No matter the condition of your rough lumber, or the ambient conditions of the season, the wood will always shrink after assembly".

[keith micinski]

^^^^^
This.

I intentionally put in the caveat: "The lumber has been sitting in the shop long enough to be fully acclimatized."

Otherwise, this becomes my Dad's anecdote about walking to school through snow, 2 miles to school and 2 miles home, uphill both ways: "No matter the condition of your rough lumber, or the ambient conditions of the season, the wood will always shrink after assembly".


I have ave kiln dried wood that has sat in my shelves for at least 5 years but probably more like 7 that shrinks every time I build a top with it no matter when it was built. I guess I have to give it a few more years of drying time.

[Kent A Bathurst]

I have ave kiln dried wood that has sat in my shelves for at least 5 years but probably more like 7 that shrinks every time I build a top with it no matter when it was built. I guess I have to give it a few more years of drying time.

Well then, Keith - let me ask you this:

What do you think is going on with your lumber that means 5- 7 years in-shop drying time is not sufficient to reach min dimension when you go to assemble?

Tell me the science / physics of what is going on - I am sincerely interested in learning. The numbers don't calculate for me, so I must be missing something.

[Mark Bolton]

I have ave kiln dried wood that has sat in my shelves for at least 5 years but probably more like 7 that shrinks every time I build a top with it no matter when it was built. I guess I have to give it a few more years of drying time.

Or climate control your shop to match your customers homes. Its more likely that your shop is simply several percent "wetter" than your customers home. High end shops are generally climate controled for this reason.

[Frank Drew]

I'll be a contrarian on the subject of breadboard ends: I don't like them and consider them fussy and unnecessary if their sole purpose is to keep a panel from cupping. There's a reason they weren't used on high-end furniture, IMO.

[Kent A Bathurst]

I'll be a contrarian on the subject of breadboard ends: I don't like them and consider them fussy and unnecessary if their sole purpose is to keep a panel from cupping. There's a reason they weren't used on high-end furniture, IMO.

Frank - You are not contrarian in my book - I agree with you on every point. But - their real purpose in my work is that they look very, very cool. And, some clients - not all - agree. But - I make sure they understand how much they are paying for "Cool", and they are always willing, if they like the look. Go figger, eh?

And so it goes..................

[Dave Richards]

Ken, although the end treatment shown in this article (http://www.wkfinetools.com/contrib/mSinger/zebraCoffeeTable/zebraCoffeeT1.asp) by Mark Singer isn't strictly a breadboard joint, you might find it makes a good alternative to a traditional breadboard for the project at hand. It would give the look your friend seems to be after and worked very well for Mark's coffee table.

[Howard Acheson]

>>>> I have had this happen twice now I might add.

You are correct the fallacy in the OP's plan is that wood absorbs moisture and expands during periods of higher humidity (summer typically) and then contracts during periods of lower humidity (winter). It never stops moving with changes in its moisture content.

[Frank Drew]

As wood ages I think over time it shrinks and expands less each season; it never stays completely still but I think the coefficient of expansion diminishes -- its ability to absorb moistures lessens. The change is subtle; I'm talking decades here, not years.

[Mark Bolton]

As wood ages I think over time it shrinks and expands less each season; it never stays completely still but I think the coefficient of expansion diminishes -- its ability to absorb moistures lessens. The change is subtle; I'm talking decades here, not years.

That sure would be nice if it were the case but I just dont think its true. Wood moves, and will move, with changes in RH of the space and MC for the life of the piece. Nothing "changes" in the wood over time. It may seem so because many pieces wind up in a home and they stay there. The piece then moves relative to the space its in. The only way to reduce the movement is to control the environment its in hopefully reducing how drastic the swings are.

The instant the environment changes so does the wood. If a home develops a roof or foundation leak, the wood will respond. Homeowner goes and cranks up the humidifier, or cranks it down, the wood will respond. It happens for eternity.

Having built homes for a living for many years I am often fearful when I build furniture for customers and am also fearful just doing high end trim work. Its amazing how many times Ive built a home and gone back later for other work and in the middle of the winter the homeowner is walking around in bare feet and shorts and the home is so hot you cant hardly catch your breath. Then you go back in the summer and you could hang meat in the house its so cold. Someone feels a little dry sinus or a scratchy forearm in the winter and they jack the humidification through the roof ignoring the humidistat saying "it feels dry". It wreaks utter havoc on woodwork, cabinetry, furniture, heck even drywall.

There is no "tempering" or "hardening off" period for wood even though it would be nice. You can take an old home full of furnishings that has been stable for years. The occupants leave, drape sheets over everything, shut down the heating/cooling. Damage will occur. There is no way around it. Its why museums control climate so aggressively.

[John Vernier]

Mark Singer's article shows an interesting solution but I suspect it is more appropriate for the relatively mild humidity swings of coastal California than for the midwest. I moved from Los Angeles to central Indiana a few years back, and all the pieces I built in LA are subject to greater dimensional changes in their new home, despite what I consider our relatively moderate home heating and cooling schedule. (I've had to rework some drawers and cabinet doors). Singer's design allows the miter itself to gap as the wood swells, and that could be a pretty large gap on a table nearly 4 feet wide. On a dining table it could collect breadcrumbs and spilled ketchup, and then nobody's going to be happy. Still, it's an interesting design.

[Ken Krawford]

Interesting approach to the problem. I'm nearly done with the project and ended up using mitered returns. I'll be curious so see how much movement occurs this summer when moisture levels increase.


Ken, although the end treatment shown in this article (http://www.wkfinetools.com/contrib/mSinger/zebraCoffeeTable/zebraCoffeeT1.asp) by Mark Singer isn't strictly a breadboard joint, you might find it makes a good alternative to a traditional breadboard for the project at hand. It would give the look your friend seems to be after and worked very well for Mark's coffee table.

[Frank Drew]

That sure would be nice if it were the case but I just dont think its true. Wood moves, and will move, with changes in RH of the space and MC for the life of the piece. Nothing "changes" in the wood over time.

Mark, I believe that wood does change over time and my understanding is that it's due to age-related cellular collapse and resulting shrinkage which reduces the water holding capacity of a piece of wood. Over time.

[Mark Bolton]

Mark, I believe that wood does change over time and my understanding is that it's due to age-related cellular collapse and resulting shrinkage which reduces the water holding capacity of a piece of wood. Over time.

Well, I believe a lot of things too. Whethet the cells are collapsing "more" after a piece of wood leaves the kiln (where it is the driest and most "collapsed" it will ever be in its life) should be easily proven with data as opposed to belief.

I'm not being snarky, but this subject has been studied and covered in the commercial wood industry repeatedly. Its well documented.

Again, if wood slowed its movement over time museums would not invest so much in climate control.

[keith micinski]

You have to be careful when making the argument "everyone else is doing it so it must be right". I think through out history that has gotten some people in to trouble. One argument for why museums spend "so much" on climate control is that there are usually very expensive, priceless, irreplaceable items in them. Every precaution needs to be taken to maintain them.