To make a removable T-assembly, nothing like an eccentric fitting fitting used in most kit furniture.
Locate on the tablet the location of the nut and on the amount that of the studs. Follow the manufacturer's ratings for the depth and diameter of the holes.
Drill with a cutter a blind hole of Ø 13mm to house the nut, then drill in the thickness of the shelf a tunnel which joins it (wick of Ø 8mm).
On the amount, pre-drill the hole in which the stud will fit. Use a Ø 3mm drill bit to facilitate subsequent screwing.
Screw the bolt making sure that it sinks in a position perfectly perpendicular to the board. This is the guarantee of a successful assembly.
Fit the stud in the tunnel: it must be inserted without difficulty and its head must come out in the middle of the cavity of reception of the nut (on the left on the picture).
Assemble shelf and amount and place the nut in its housing. It only takes a quarter of a turn to tighten the stud and ensure a solid assembly.