Attaching table top to allow for expansion

[Doug in Burlington]

Hi, looking for opinions on what to allow for expansion on a coffee table that I am just finishing. The top is about 32" wide by 62" long made up of about five pieces of 4/4 red oak that I have joined together. There are runners down the length of both sides of the frame that it sits on. I was planning on putting six screws down each side, spaced at about 9". One side would be through a fixed hole and the other side I was going to slot the hole in the runner about 1/2" to allow for expansion. Will this be sufficient? I was going to slot both sides but the frame it sits on has drawers underneath. THis means that the runners on one side are above a drawer support and making slotted holes that I can access through the drawer support will be difficult so was hoping having the top fixed to the frame on one side and able to move on the other would be ok? If this is as clear as mud I will try and sketch up something .

[Mike in Waubaushene]

I use these from Lee Valley. I use a forstner bit to drill a hole in the apron that is cut over the inside edge. I use 3 on each end and every 15 inches or so. Screw snug but not overly tight. They are designed to allow wood movement.


http://www.leevalley.com/en/hardware...306,41309&ap=1

[Roy in Thunder Bay]

Doug:- 1/2" of slack across 30" between the screw rows will be fine. You can determine the expected material movement using your own environmental conditions if you google "shrinkulator". Have found it very handy. Roy

[Doug in Burlington]

Thanks Roy, calculator looks like it may come in handy.

Mike, don't think I will use those for this project but they look interesting. How do they allow for wood movement? It would seem that the only way they can move is if they swivel but as soon as you put two at 90 degrees to each other they will no longer be able to swivel, or am I missing something?
THanks for the quick response.

[Mike in Waubaushene]

They do swivel a bit. Where the drill hole recess breaks the side, I use a box cutter to open that a little more on each side. On the long sides of your table, movement is not very noticeable. The expansion and contractions will be across the ends as the wood moves. Another method I've used is cutting a slot near the top of each apron side and then cutting wood clips attached to top. They slide in slots. But since you had already put everything together that is not an option. Your idea of a runner on inside of the apron will work as long as you elongate the top side of the screw holes in the direction of the expected movement.