Oversized MakerBot Idler Pulley

thingiverse

For those with smaller z-axis drive pulleys and ACME threaded rods, belt tension adjustment is usually at the lower end of normal range. To ensure standard adjustments, oversized hubs are used for these pulleys. For detailed instructions on ACME Rod installation and tuning, refer to this link: http://abella.net/?page_id=306. In case you have altered your z-axis mechanics significantly, you may require additional parts to print, insert a standard skateboard bearing, and mount it properly; otherwise, these are probably unnecessary.