625 bearing idler for MK3

thingiverse

Here's a simple idler door upgrade that swaps out the standard MK3 idler for one featuring a second Bondtech gear paired with a 625 bearing. I'm not entirely convinced it makes a difference, but it certainly doesn't cause any harm and eliminates the pesky "rust" between gears. To give this upgrade a try, you'll need to source a 625 bearing and a 4mm round rod - I opted for an M4 bolt with the head removed.