A simple magnetic tray created in Shapr3D, requires 3 x 30mm x 3mm and 4 x 15mm x 4mm magnets. Original model included that is parametric allowing different magnets to be used.
Turns out the 30 mm magnets are 29.75mm for snug fit, the 15 mm are 15.25 for snug fit.
The magnets do not require glue but a little cyanoacrylate (Super Glue) would help stop them coming out.
Printed in PLA with a colour change for the top layer. 0.2mm Speed Profile with support on build plate to allow the holes for the magnets to work correctly.
15 mm from Amazon Here: N35 Neodymium Magnet for Arts, Crafts, Model Making, DIY, Hobbies, Office and Home - 15mm dia x 4mm thick - 2.8kg Pull - Pack of 10 : Amazon.co.uk: Business, Industry & Science
The author marked this model as their own original creation.