Open XY blocks with adjustable belt tension - for original Ultimaker (8mm gantry rods)

thingiverse

These blocks can be easily swapped without dismantling rods and pulleys, after removing the originals. Adjustable belt tension is achieved through a banana cam. The gantry simply detaches without undoing blocks. 6mm rod version soon! Print parts with 0.1mm layer and 100% infill; required components per block: 6 M3x6mm socket bolts, 5 M3 nuts, 1 square nut, 2 tubes (3mm inner diameter, 6.3mm outer diameter, 6.5mm length). Prep all parts before dismantling the gantry, rods, and pulleys. Assemble rods, belts, and pulleys normally; secure journal bearings only. Insert blocks on rods and add key wedges without tightening. Slide blocks over bearings and slightly tighten bolts. For each block: place square nut in captive location, screw bolt through nut, slide banana in place, and capture belt under hinge screws passing through tube cuts as rollers. Position gantry and secure rods on blocks with brackets; gently tighten bolts. Tighten belts using adjusting bolts to remove slack and create a tone; balance for uniform sound. Don't over-tighten! Square the gantry and tighten pulleys, possibly using Loctite Blue. To loosen later, use heat or acetone. Level platform and print away! Enjoy your improved printer. If you like this design, consider donating for improvements at [PayPal link].