Keyring magnet

A simple keyring thing with an embedded magnet. I use a pair of them to keep my car keys and house keys together. This lets me keep the house keys in my pocket so I don't have them bashing against my knee when I drive.

I used these [4 x 8mm magnets](https://www.first4magnets.com/circular-disc-rod-c34/8mm-dia-x-4mm-thick-n35-neodymium-magnet-1-47kg-pull-p6222#ps_0_6417|ps_1_6658)

#Printing notes
0.1mm layers look nice, but 0.15 worked fine too.

You will need to add a pause to insert the magnets. I did it at the 4.5mm layer change and inserted this GCode:

; Pause to insert magnets
G1 X10.000 Y200.000 E0 ; parking position
; Move print head up proportionally of print height to max
{if layer_z < max_print_height}G1 Z{z_offset+min((layer_z/max_print_height)*(max_print_height-100)+100, max_print_height)}{endif}
M400 ; Finish moves
M300 S2500 P1000 ; beep
M0 Add Inserts ; User stop with message
M105