Magnetic Carriage for StrongPrint http://www.thingiverse.com/thing:329498 Based on Supermagnete 15 mm donut magnet http://www.supermagnete.fr/eng/R-15-06-06-N The use of magnetic bearings (steel ball over a donut magnet or vice versa) allows 3 key advantages: These could be fitted with contact wires to check if there is a loss of a link & inform the control unit to stop or hold the print job The chosen magnet are just sufficient for the StrongPrint head therefore if you intend to use a heavier print head you should choose to take slightly more powerfull magnets.