I recently decided to check the overhead gantry for play. I found I had a little bit of play developing on both the "Y' guild rollers and "Z" guide rollers. Most is due, I am sure to things settling in after getting some run time on the machine.
One problem I had is with the "Z" axis guide roller adjustment. If you will remember that the right side guide roller adjustment is fixed and the left side roller guides are adjustable. This setup may lead to play on the right side guides, that can't be adjusted out because the Z axis lead screw is fixed in place. The play I have in the right side guides is small but there is no way to remove it unless you slot out the holes on that side of the mounting plate. No worries its easy to do and you only need to do a little work with the dremel to open it up.
This got me thinking. If you replace the original flex tool with a roto zip or another type of heavier cutting tool in place, the added weight may exasterbate any slop in the guides, causing inaccurate tool cutting paths.