Delta 6x48 Sander Tracking

• Both pulleys/drums must have a proper crown. See Drums.
• The upper idler drum assembly may be flopping around in a worn track for the two steel side guides that go down into the main casting.
• Reversing the direction of the belt may improve tracking.
• Try lubricating the entire tension/tracking mechanism.
• Check the tension/tracking mechanism for burrs. If found, filing them down often corrects tracking problems.
• Sheet metal platens are known to cause tracking issues. See Tables, Fences and Stops.
• Try a different belt. An outside possibility is that the belt isn't joined straight or it has stretched in the middle from being stored on the machine under tension for extended periods of time.