I’m building a bookshelf out of MDF (18mm thick) using 6mm dowels (Silverline brand like the dowelling jig). Each shelf will be dowelled in place at the back and on both sides.
I’m concerned about whether the dowels will be strong enough for a heavily loaded shelf.
Is there a formula or rule of thumb that says how many 6mm dowels are required (or even what distance between dowels is required) to support a given shelf load (in kg) assuming the shelf is supported only by dowels on 3 sides?
I’m planning for the dowels to be glued. Are there times when dowels are not enough and the shelf should also be glued, screwed or nailed in place?