Thread: Wood movement on slatted table top

In general u don't need to worry too much re board movement if u keep your width of board to less than 50 to 75mm, with your design tho and it being outside id consider fixing positively (spot of glue/screw) on one side of the board then allow it to move for the rest of the width of board, as it is held in a slot the board then is held against any oomph movement/twisting/cupping but allowed to move across it's width as long as u have a gap between each board allow ~2mm/100mm width of board
You also could use buttons/figure eight brackets (in the shape of an eight) to hold down the frame to the aprons but u just wont need to worry too much about movement because each board is allowed to move within the frame.
The corner leg to apron brackets adds strength to the corner, if the piece is likely to get moved about a lot it is a good idea


Pete

Hi John,
The batten will stiffen up the slats as each slat then helps to support the one next to it, to add the batten apply the same design thinking... fix one side but then allow the remaining width of slat to move, I wonder tho if u actually need to use it, the slats unless they have ended up rather thin should have enuff stiffness to support the usual table stuff, the slats are from step treads so I take they are dry hardwood so if they ended up 19mm thick and say 100mm wide and ~1000mm long that would be pretty much self supporting


Pete

I have decided to add the battens for a bit of extra support.

Pete's last post about my slats maybe being 100x19 really got me thinking about my design. Well it's not really my design, I copied it from a table I saw at a large outdoor furniture retailer with slat dimensions 75x15. In hindsight I don't know why I copied every dimension from the table I liked. Maybe a novice's lack of confidence in a design?

Maybe I should have looked at the timber I had and worked out how best to utilise it from an efficiency (wastage) and aesthetic point of view. The step treads were 250x50 so of course I could have made the slats much wider. And 19mm thick could have been achievable, although I think I need more practice at setting up my bandsaw for resawing more accurately.

Lots of money and time has been spent but importantly many lessons have been learned and skills gained. A couple more days ought to see it finished and then I'll have to think of the next project.

1. I'd pin the centre of each batten from underneath the tabletop to prevent sideways movement and forget about glue... mainly to avoid issues with suitable adhesives.

2. What PJT said. Assuming you fasten the buttons to the tabletop's frame, and not the battens!

3. Corner brackets aren't a necessity, but they do add strength to the joint. Many flatpacks use these with plain ol' butt joints instead of M&T. (I'm not suggesting you do this, just pointing out that one of the reasons these brackets have become so popular is that they remove the need to make the joints right! )

If you're expecting the table to be dragged around a bit outdoors, then they're probably a good idea just the same.


Good luck with the table! (And with the other half. )

I have decided to go ahead and install the corner brackets to reinforce the M&T joints. Besides, I spent money on them so I have to use them!

Now I am wondering how exact do I have to be when I install them. Do I need a Masters Degree in Advanced Geometry?

From what I can see I need to:

- put a chamfer on the inside corner of each leg between the two aprons
- use a coach screw to attach the bracket to the leg through this chamfer
- put a dado on each of the aprons to give the little lip at the end of each wing of the bracket something to grab on to
- drive a few extra screws into each wing to firmly secure them into the aprons

I would have thought that the relationship between the size of the chamfer and the location of the dados along the aprons would have been fairly critical?

I have drawn it all up to scale, overlaid the bracket, and reckon "it's about right". Should I just go for it or should I make up a "mock" leg joint with two aprons and try my measurements out?

Are there any tricks, is there a better sequence of events, or are there things that I am missing?

Cheers,
John

Originally Posted by JohnMurray71

I have drawn it all up to scale, overlaid the bracket, and reckon "it's about right". Should I just go for it.....
famous last words
or
should I make up a "mock" leg joint with two aprons and try my measurements out? John

I always like to do a test piece just to be 100% sure

It would be good practice to do a mock up first, it then allows u to see if u have the dimns right (or wrong), the bracket is a bit useless if u end up with the lippy bits not engaging with the side of the notch with the nut fully done up.
It should pull it all together tightly when u do up the nut.

Pete