# When Should A Joint NOT Be Glued?



## Wood4Brains (Jul 25, 2012)

Hi there, Everyone:

Another noob question: When should you _*NOT*_ glue a joint together?

I have heard that when joining certain pieces together that, due to the naturally occurring expansion and contraction of the wood, there are times when you should *NOT GLUE* pieces together and should *only* use screws instead.

So, Is there any "rule of thumb" for when it is ok to glue joints, and when it isn't? 

Thanks in advance for your help and your patience in dealing with my noob questions.


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## Greg in Maryland (Jan 6, 2011)

A few that come to mind (there are many more)

-- breadboard ends (google breadboard end for an example)
-- certain types of doors - raised panel with rails and stiles. Think, kitchen cabinets.
-- affixing table tops to table bases
-- knock down joints, where disassembly is required

That's a start, though there are many, many more examples where lots of glue isn't the answer.

Greg


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## Lola Ranch (Mar 22, 2010)

These wedged trough tenons are not glued in case you want to move the table. Just knock the wedges out and pull the stretchers out of the leg assembly.

Bret


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## Wood4Brains (Jul 25, 2012)

Hi there, Greg and Bret:

Thanks for the answers.

I hope you can explain further about this one:



> -- affixing table tops to table bases


Is that specifically to allow for expansion / compression? Or is that to allow for it to be disassembled?

Also, suppose that you made a long carcass (maybe 3 feet by 3 feet by 6 feet long) that you were going to cover:

1) Would you glue the joints of the carcass together?

2) If you covered it with hardwood, would you glue it to the carcass?

3) If you covered it with PLYWOOD instead of hardwood, would it then be ok to glue?

Thanks again.


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## FrankC (Aug 24, 2012)

Anytime you have wood with the grain running in opposite directions there is going to be more movement in the width of the board than the length. This is where design comes into play to allow for movement and why certain configurations don't work such as a mitred frame around a glued up panel.

Generally the table frame has a rail across the end with the grain running lengthwise so it will not expand as much as a top with the boards running in the opposite direction to that of the rail.

End panels or side panels are no different than a top so the same design elements have to be considered, which is why loose panels are so common.


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## Wood4Brains (Jul 25, 2012)

*@ FrankC*



> Anytime you have wood with the grain running in opposite directions there is going to be more movement in the width of the board than the length. This is where design comes into play to allow for movement and why certain configurations don't work such as a mitred frame around a glued up panel.


Thanks so much for the explanation. That was what I THOUGHT that I had read, but wasn't sure.

Any more tips anyone on when NOT to glue? These have been great so far.


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## matt woodwork (Sep 1, 2012)

Tenon joint with and off centre dowel in seasoned or green timber will pull a joint tight as f . You gotta play and find out with your chosen timber and environment !


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## Midlandbob (Sep 5, 2011)

Sometimes it is what PART of a joint not to glue.
Breadboards- a few inches in centre. This allows the sides to move in and out with the seasons around the pegs in slots.
Any wide cross grain situation only a small area can be glued.
Raised panels- sometimes a touch of glue in the middle of the ends of the wide panel are glued. This again lets the sides move in and out but keeps it centred and it minimises rattling in a door.
Bead headboard- I'm just finishing a shaker cherry headboard. The top tenon will be glued but the bottom one left unglued in a wider mortise to allow movement.
Repeating the takedown furniture. I have left tenons in table rails unglued but put in a pocket screw on the inside to allow the able to be easily taken apart for moving. A three inch tenon on 4 inch rail leaves an inch for pocket screw.
Drawer bottoms but that's just a different raised panel. Gued or tacked athe front only to let the back move.
I have used the tasked tenon as mentioned on trestle table or bench.
Round joint in chairs if used a wedge or tapered tenon.
Tapered dovetail joint holing on table top or bench etc..
Maybe more?? I'll keep watch


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## davidpensfan87 (Apr 16, 2012)

When you want to take it apart, like a bed frame. 

Also, and I'm sure someone has mentioned this, you shouldn't glue the panel when you make raised panel doors. When someone says the panel is floating, this is what they are referring. The reason for this is because the stiles and rails will change size as the seasons change, so if the panel is glued in, and the rail would happen to shrink and get narrower, it would split the wood. This is the same reason to pre finish panels before assembly so that when the rails and stiles shrink, there will not be an unfinished section of the panel visible.


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## Midlandbob (Sep 5, 2011)

It's the panel's movement that caused the invention of the raised panel and avoiding gluing the sides of the panel. 
Early doors built with boards side by side moved too much for the door frame or had lots of cracks between the boards so raised panel doors were invented.
The styles and rails are usually narrow with minimal movement. The panel is wide with the potential for a lot of movement. If the sides are glued to the stiles the panel wil possibly be pulled apart,split.
Just FYI not to offend.


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## HandToolGuy (Dec 10, 2011)

There are joints that do not require glue but the joint has to be tight. Through mortises and dovetails come to mind.


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## USNRET (Oct 28, 2012)

*Biscuit's*

I am new to this forum and I have a question.
My son was with Me when i bought a Biscuit joiner or Plate Joiner, I told him that we were going to Lowe's and buy Biscuits. he looked at me funny and said Dad, Lowe's does not sell biscuits. I told him they do. When i got back in the truck, I let him look at the jar of Biscuits and he said Dad those are foot balls.
My son would like to know , Why are they called Biscuits? when they are not round? 
I can not answer him so I thought I would ask on here.
Jim Bell
USN RET.


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## Midlandbob (Sep 5, 2011)

Hunted in Wikipedia about the invention etc. no mention given.

Possibly as the biscuits are specially cooked. They are usually made from bake to extreme dryness and compressed at great pressure so the glue causes quick expansion from the moisture added to the pre shrunk cooking of the "biscuit".
The oval shape comes from the small saw that sticks out a bit leaving two parts of a small circle hence football shape.


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## USNRET (Oct 28, 2012)

Thank You for the reply. I sent your reply to my son. he like to argue with me about Biscuits. I sent a e-mail to Norm at NYWS and he didn't reply. 
Jim:laughing:


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