Parametric Music Stand Magnet

Chords and sheet music fresh off the printer have an annoying tendency to curl up and slip away. Clips are irritating and make it slow to turn to the next piece of music. For me, the answer is these magnetic pushpins. The provided STLs are designed for 6x2 neodymium magnets, but it is parametric - you can edit the parameters in the OpenSCAD file and generate a pin model to suit just about any disc-shaped magnet. The 6x2 magnets work really well indoors, but if you are wanting to hold your music against a stiff breeze outdoors, you might need to upgrade to something with a bit more holding force.

Instructions

1. Adjust Parameters

If you are using 6x2 magnets, you can skip this step. For other
magnet sizes, edit the values for mag_diam and mag_thickness below.
The other dimensions will automatically resize accordingly, but you
can adjust them if you wish.
The intention is to have the 'hollow' for the magnet one layer
above the base of the model. Set the value pf layerheight to the
layer height you will be printing with.

2. Slice

The model prints easily, no supports or brims or anything required.
You do need to get your slicer to insert a pause just before 
printing the layer that covers the magnet void. This allows you to
drop your magnet in, and when the printer resumes it will seal it 
in, nice and tidy.
In Cura, you do this by:
Extensions -> Post Processing -> Modify G-Code -> Add a script,
select "Pause at height".
I set it to pause at layer number 13, which was perfect for a 2mm
thick magnet and a 0.2mm layer height (it's easy to identify the ‘right’ layer by slicing and previewing). I also had it do a retraction before the pause.

3. Print

Print the model as usual. When it pauses, drop the magnet into its
socket, and using a non-metallic object (plastic pen caps work well)
tamp it down. Be careful not to bump the printer or the model while
doing this - a nice, delicate touch. Resume the print and... voila!