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

These blocks can be replaced without having to dismantle the rods and pulleys, after of course removing the original blocks. The belt tension is adjustable through a banana cam. The gantry can be easily removed without undoing the blocks. The 6mm gantry rod version will be posted soon.

3D printer parts and enhancements

Creative Commons Attribution Share Alike

Commercial use is allowed, you must attribute the creator, you may remix this work and the remixed work should be made available under this license.

Learn more or download attribution tags


Make sure you have all parts ready before dismantling the gantry, rods and pulleys!  
Assembly:  Re-assemble the rods, belts and pulleys as normal without the blocks, just the brass journal bearings in place. Don't tighten the sync pulleys, but tighten the driving ones (motors).   Place blocks on the rods and assemble the key wedges, don't tighten. Slide in place the blocks over the journal bearings. slightly tighten the bolt.  One block at a time:  Place the square nut in its captive location.  Screw the bolt few threads through the square nut.  Slide the banana in place.  Capture the belt under the hinge screws passing through the tube cuts acting as rollers.  Position the gantry and secure rods on the blocks using the brackets. Gently tighten bolts.  Tighten the belts using the adjusting bolts, enough to remove slack and hear the belt give a tone. You can balance all belts to give the same tone. Don't over-tighten!  Square the gantry and tighten the pulleys. You may want to use a thread locking compound like Loctite Blue. Remember that to untighten later, you will have to heat the grubscrews or use acetone to dissolve the thread lock.  
Level the platform and star printing.  

Materials and methods

Required parts for each block:
6x M3 M6mm socket bolt
5x M3 nut
1x M3 square nut
2x tube (3mm inside, 6.3mm outside diameter, 6.5mm length) plastic or metal. I used cuts from my old Bowden tube.



Issues are used to track todos, bugs or requests. To get started, you could create an issue.


Mini kneuLEprinter added this to the UM collection ago
869895cdecbaeba230a187715a18d53b?default=blank&size=40taylan added this to the aaa collection ago
Bcbf3000397afde5dd1875cf5476e84b?default=blank&size=40wowowaa added this to the CTC Giant collection ago
Ba2dfb12d93b502c89b217fbec54a300?default=blank&size=40perlguy added this to the Ultimaker collection ago
60950dd31917645cf7066679bdd307f7?default=blank&size=40Petrica Dragusin added this to the ultimaker collection ago
46a0e54a71b82680dfbfdc5c217265b9?default=blank&size=40Murat published this design ago