X movement does not match command, Y movement does

[Wisar 86]

When I measure actual versus commanded movement it seems my Ultimaker 2 is NOT obeying me on the x-axis though it seems to be on the y-axis. A movement command of 100mm on the x-axis yields me an actual movement of around 98.9mm. Command of 60mm yielded 59.7. Command of 10mm yielded 9.9. Similar commands on the y-axis were accurate. Measured using a mechanical pencil tied to the printhead so I am pretty confident of my measurement accuracy.

All of the belts feel the same...the y-axis and x-axis short belts and long (though frankly this is really tough to measure)!

Should I try to further tension the short x-axis belt or is the something else that could be the cause?

Thanks,

Wisar

[Wisar 86]

Tightening all of the set screws on the gears for the x-axis pulleys seems to have corrected this issue.

Wisar