Delta 31-450 Belt/Disk Sander

Model 31-450C which I think is the same as the Delta 460 Type 2 purchased in 2004. Suffered a sticking, that is slow to start rolling, over heating idler roller in early 2005 and repaired under warranty by "realigning belt to pulleys".
Same problem one months later. Repaired under warranty by "relube of roller" and check over.
Mid 2006 same problem again and the bushings and idler roller were replaced under warranty.
In April 2007, now out of warranty, the problem recurred and I had to replace the idler roller, idler shaft and bushing again due to heat damage and wear of the shaft. This time I paid for the parts and installed myself. Now the problem is occurring again.
I can't help but think that there is something fundamentally wrong with the design. I am a hobby user. I make two or three large pieces of furniture a year. This tool is not getting heavy use. After perhaps five minutes of running time, the tracking adjustment metal parts are too hot to handle. There is way to much frictional heat building up. Should I be packin g the idler roller and shaft with grease? Is there a replacement unit with better bearings? The Delta WEB site is of no help. Any ideas would be appreciated. It's getting to where I would spend more on parts maintaining the tool than it cost originally.
If the consensus is that I should start over recommendations as to an alternative manufacturer's tool would be appreciated.
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