question on wood movement with breadboard ends

[monstrol]

If I laminate a 3 inch thick table top that will have breadboard ends. Should I still fabricate the ends so they float to allow movement?  I  plan on using 5/4 rift sawn white oak to make the top.
Any and all input is appreciated.

 

[Bohdan]

Unless you have a constant climate room in which to keep the table and the timber has been acclimatized for a long time in the room the top will shrink and expand far more in width than the ends will change in length. If you don't allow the movement the top will split, either on the joins or thru the timber.

 

[Linbro]

There's a great article here, on breadboard ends:
http://festoolownersgroup.com/festo...board-ends-demonstration/msg231732/#msg231732

 

[tjbnwi]

Quater sawn and rift sawn lumber are both very stable. They expand in thickness more than width or length.

Plan for some movement but not as much as plain sawn.

Tom

 

[monstrol]

So laminating the 3 inch slab and staggering the joints won't eliminate enough of the movement?

 

[tjbnwi]

I do not see the size of the slab mentioned.

What do you mean by "laminate" the 3" slab? Define what/how the laminations will be created?

Tom

 

[Jesse Cloud]

If you laminate the pieces with the same orientation, even if the joints are staggered, there will be little change in the movement - it still move a significant amount.  If you run the laminations at 90 degree angles, as in plywood, it will soon break apart.

The reason laminates like plywood don't move is twofold: 1)the plys are at 90 degrees, and want to move in different directions and 2) the plys are very thin, and less susceptible to movement.

The purpose of a breadboard end is just for show - it hides the end grain.  It does not stop movement.  The breadboard captures a thin tenon from the slab in a groove in the breadboard.  Only the middle of the slab is glued or permanently fixed.  The rest is allowed to float and move.  The slab will grow and shrink in and out of the breadboard.

For a slab that thick, I would suggest leaving the ends open and attaching the slab to the base only at the center.  You might add some battens at the bottom of the slab to encourage the slab to stay flat, but attach them with screws through slots that allow for movement.

 

[Stephen B]

[size=13pt]Using the experience of The Bicycle Cafe [see reply #3], in the following thread I discuss how I recovered a movement issue with vertically laminated recycled Australian Mountain Ash Countertop -
http://festoolownersgroup.com/member-projects/my-magnificent-failure-(and-recovery)/msg281207/#msg281207

The first image is a recent photograph of the Counter Top installed on a renovated Island Cabinet. It was attached using Domino Block Buttons which allow movement in a similar way to commercial table buttons.

The second image is a countertop with no bread boarding made by laminating 15mm thick strips of recycled Merbu Decking. This had more staggered joins than the Ash top. Being thicker there has been little movement.

Both Countertops were finished with OrganOil Hard Burnishing Oil following the Festool Surefix instructions. The Merbu was also waxed.

[size=8pt][member=13507]thebicyclecafe[/member]
[member=14551]Linbro[/member]

 

[monstrol]

Thanks for all your input. I am planning to laminate the top with 3 layers of 5/4 rift sawn white oak, edge glued and laminated together with staggered joints and flipping grain orientation, no wider than 10 inches so as to joint, edge and plane each glued up slab prior to edge gluing each dressed slab for a 39x84 inch table top. It will have 2 turned pedestal bases that will keep the top floating. It seems the general concensus is to just assume the wood is going to move so I will make the necessary fabrication adjustments to the breadboards.

 

[JimD]

Yep.  Wood moves.  If you apply a finish to all sides that sheds water (like poly) you can slow it a lot but it is still going to want to move.  That table top is wide enough to have significant movement.  You have to allow for it in the design, as you said.