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I am making a dinner table for my daughter, quarter sawn white oak, trestle style, and plan to 'breadboard' the ends. My question is not how to make the joint (probably spline, but maybe tongue & groove) but rather this: Do I glue the entire length of the joint, or will that cause problems as the wood moves during the seasonal changes? If anyone has experience or insight into this type of construction, please advise.
 

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Welcome to the forum....I will let the more knowlegable answer the tech question.....I have done a few bread board edges, and I used a table saw to cut a rabbit, and then a dado stack to cut the groove. Glues solid. No problems, but then again, I might not have done it correctly.
 

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jim welcome. don't glue the joint at all. it will not move much along the length of the long grain will do so over it's width. The breadboard has to be able to accomodate the movement of table top in its' joint whether it be a spline with doweled mortise and tenon, or a dovetail joint.
It will react to the RH changes and eventually if you try and restrain it, it will break free from its bonds and make you pay. Could be weeks could be years but if you glue the joint it will suffer some degree of damage.
 

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As an addendum it could be argued that it's cool to glue the center mortise and tenon but I don't even like that just glue the dowels in place , and remember to elongate all the dowel holes in the tenons except the center one. It, you don't want to elongate so that it will be held in place.
 

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Pretty much ditto what TT said. I always use a tongue and groove. I make two elongated holes in the tongue and put the dowels in from the bottom.
I made a window seat from red oak about a year ago and though it's only about 18" wide, it moves about 1/8" with the weather.
 

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Discussion Starter · #6 ·
O.K., this is starting to make some sense now. I suspect I will be using a tongue and groove joint, but in order to accomadate the dowels, it looks like the tongue will need to be longer than I had anticipated. I had investigated the possible seasonal dimension changes (Understanding Wood, by R. Bruce Hoadley) and was quite suprised as to how much this table will change. As far as choosing which joint to use, I guess we are limited by our tools we have, but I do have the confidence to proceed knowing that this table will withstand Minnesota's brutal moods. Any more input will be great, thanks so much.
 

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The tongue only has to be 1/2" wide and the dowels 1/4". I keep my dowels a tad closer to the panel side.
I also make my joint fairly tight so there is no slop up and down. Not tight where you have to get out a mallet but so it doesn't want to slide off the tongue.
 

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After reading this, I guess I wasn't doing a true, breadboard edge....but the first one I did is still holding perfect after a dozen years...of course, there isn't really a lot of humidity changes in my home.
 

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I think the key here is, will the table be subjected to huge humidity swings. If the table is kept indoors in a climate controlled house, it should never move. If you like to open you windows for most of the summer then it will move as the humidity goes up and down.

As far as how the old craftsman did it, it was because in the summer there was no airconditioning and in the winter they heated their house with wood heat. Your talking about a possible 50% swing in humidity.

I think that in todays society with the way most of us live if it was glued all the way it will probably hold up for the rest of it's life. If you want to do it the old craftsmans way then dowl and glue only in the middle like the above post.
 

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Even under the best of circumstances who in the world can guarantee a piece of furniture wont be subjected to RH swings? Even in todays society.
Hope for the best and plan (build) for the worst as the old addage goes. Gluing along the length of the joint is planning for disaster.
 

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In my experiences, as long as the environment changes aren't extremely drastic, then you can do the glue. Most of my projects get built in my garage, which has a duct fed from the house. I run a heat pump year round and have little change in humidity or temperature. I have yet to have any warps, cracks, or issues. You could try it and if it does have issues, cut back and do a wider breadboard with no glue.
 

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I'm not trying to argue here and certainly not trying to say i am "right" and you are "wrong"; just want to clarify a litte further my viewpoint.

When you say "In my experience" you nor I have even been on this planet for a very long time. When I build a piece of furntiure i want it to last generations. To assumne that a piece is never going to be exposed to RH swings is simply not realistsic nor thining in the long term.
That's really the only reason to use this fail safe, centuries-proven method though. If 10 - 20 years is good enough for you by all means glue the joint and pretend it will never fail and that it wil always be kept in a Smithsonian environment.

Now this is just my opinion and I my way is not the only way. I just want newbies to realize when you glue to pieces of soliud wood, perpendicular to each other according to the grain such as in a breadboard, the wood is going to move unless it lives the rest of its life in a perfect environment.
i don't think you will find any woodworking school, respected instructor, or respnsible publication that would teach otherwise but I stand to be corrected.
 

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Ok:yes: , You make a very valid point that you cannot predict RH changes. I think each case is different and if I was building a piece that I was worried about wood movement...no glue.

However, should you decide to glue, make sure the wood is a environment that matches the same relative environment as it's final resting place (for a short period of time or while being built) to reduce the chance of splits and such. This is the point I guess I was trying to make.

The last few projects I've done have been tables that I didn't want a joint crack open for liquids and such to get into and expand the wood. Glueing/sealing the joints was a more appealing option in my opinion.
 

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I concur with TT. In fact, when a client wants a price for a piece of furniture, custom made, I ask them if they want heirloom quality or something that will just last our lifetimes. That may sound odd, but I can scare someone away with a price for an heirloom piece that takes more know-how, talent, time and materials.
A breadboard end is a good example.
 

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The last few projects I've done have been tables that I didn't want a joint crack open for liquids and such to get into and expand the wood. Glueing/sealing the joints was a more appealing option in my opinion.
But here I bet you are referring to long grain parallel to long grain where a glue joint is unequalled in performance.

It's just when you glue long grain perpindicular to long grain that a glue joint can eventually fail over a long peroid of time. Think about how wood moves mostly ... most of the movement occurs across the grain, so in the case of a breadboard the top, not the ends, move along the glue line but the end board cannot match that movement in the same direction becasue tangential movement is very minimal in wood.

So your glue lines with long grain parallel to each other is prcatically immune to failure all things being equal (proper prepration and execution) even when disimiliar woods are used, because expansion and shrinkage are so minimal in that direction.
 

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TT, I don't dis-agree that no glue is the right way to do this. I just think that it depends on the environment and use of the piece. If the piece is for every day use and in an environment that would be suitable, glued joints look good and serve a purpose. In my case I didn't want moisture and junk falling into the cracks. I've done several projects this way over the years and I haven't had issues yet. Some my projects are close to 25 year old, not that this is old, but still they've had time to adjust.

So what would be my or Jim's options if the joint wasn't glued and wanted to be sure the joints were sealed? How does one go about doing this? What methods would you suggest?
 

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A well executed breadboard joint, especially a dovetail, will not be the huge crack you are envisoning and will be barely discernable. If you glue it, it is going to break the seal of the finish eventually anyway and have the same look.

Click here for a step by step illustartion of a classic breadboard approach using mortise and tenon. It has no visible gap to speak of. A dovetail joint will be even tighter.

Here is another Link.

If you want to glue it then by all means glue it. :thumbsup: It won't explode and set the house on fire if you do. :laughing:
 

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This is the window seat I was talking about a few posts earlier. This picture was taken last week when the temps here in DE were in the 60's with humidity about the same. Notice how much the breadboard is proud of the panel. In the summertime, even with the a.c. on, the panel expands a little more than that. Make this a 48" wide table top and multiply the expansion/contraction. My point being that with all this movement, something has to give.
 
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