Timber movement

[Aussie]

Currently doing another tray 480 x 400mm approx.
The base for the tray will be end grain, thickness 12mm with inlays, this base will fit into slots in the frame 12mm high and 5mm deep and will be floating.
My question is how much do I allow in the slots for the end grain expansion / contraction? So the tray frame will remain flat and square.

Thanks

[Tailmaker]

Hard to say, will depend on wood species and humidity changes.
I would not ever make such a piece again. Many years ago, I built a table from a large piece (1m x 2m) of end grain butcherblock pine. Since it was still too small, I expanded that with flat grain boards all around, i.e., similar situation like yours but with no expansion gap.
After a few weeks it developed cracks up to 1 cm wide. I "fixed" that by routing a few channels into the underside and forced the cracks shut with threaded rods. Kind of worked but again, this is calling for trouble.

[Aussie]

Thanks for your advice.
Will make the item and leave it in my shop for a couple of months and see what happens..... maybe more firewood

[Rcnewcomb]

The good news is that you live in an area with fairly stable humidity.

[Aussie]

That’s true in Adelaide however this will be a gift for a friend in Singapore which could be a problem