Note for anyone struggling with belt tuning at this step:
At this point in the build, my belts were already very loose — so loosening them further to align the gantry made no sense. Also, both the tuning app and website failed to measure belt frequency reliably when the belts were too slack.
Here’s what worked for me:
1. Check gantry alignment: Pull the gantry all the way forward. If one side has visible play (in my case, the left), slightly tighten just that side to reduce the slack pulling it backward.
2. Stabilize the gantry: Once both sides sit firmly with no flex or rocking, push the gantry all the way back and center the printhead along the X axis.
3. Start tuning: Try the tuning website/app. If it can’t detect the frequency or gives inconsistent values, tighten both belts equally — half a turn on each side. Repeat until the belts feel noticeably tight — there should be a good amount of resistance when moving the gantry by hand.
4. Dial it in: As the belts approach proper tension, the tuning tool becomes more reliable and starts reporting consistent readings. Use this to fine-tune into the recommended Hz range.
TL;DR: Instead of loosening everything, start by tightening the side with play. Then move the gantry back and begin tensioning both sides equally. As the belts tighten, the app/website becomes more accurate. Periodically move the gantry fully forward to spread tension and re-check alignment.
At this point in the build, my belts were already very loose — so loosening them further to align the gantry made no sense. Also, both the tuning app and website failed to measure belt frequency reliably when the belts were too slack.
Here’s what worked for me:
1. Check gantry alignment: Pull the gantry all the way forward. If one side has visible play (in my case, the left), slightly tighten just that side to reduce the slack pulling it backward.
2. Stabilize the gantry: Once both sides sit firmly with no flex or rocking, push the gantry all the way back and center the printhead along the X axis.
3. Start tuning: Try the tuning website/app. If it can’t detect the frequency or gives inconsistent values, tighten both belts equally — half a turn on each side. Repeat until the belts feel noticeably tight — there should be a good amount of resistance when moving the gantry by hand.
4. Dial it in: As the belts approach proper tension, the tuning tool becomes more reliable and starts reporting consistent readings. Use this to fine-tune into the recommended Hz range.
TL;DR:
Instead of loosening everything, start by tightening the side with play. Then move the gantry back and begin tensioning both sides equally. As the belts tighten, the app/website becomes more accurate. Periodically move the gantry fully forward to spread tension and re-check alignment.