Curious band behavior

[John357]

I've had 2 bands do this within an hour, and wonder if anyone else has seen it.  The band comes off the idle wheel, and then bunches up in front of the first guide block.  The band rises in front of the block to about 5 inches, and then doubles back on itself, still in line with the blocks adn still on the drive wheel.   Band comes off in front of the idle wheel.  

Guide blocks are all adjusted recently, newer belts, the second band was new.  I suspect the drive belt might be too loose, I can deflect it with my finger about only 1/4 inch (spec) or 1/2 inch.  Was adjusted last summer, not much milling for me since then, but maybe it stretched out a little and is causing this.  

I'm running the Woodland Mills HM126, standard 10* blades from Woodland Mills, cutting Tree of Heaven (Ailanthus) 12 inches wide; so, no trouble there.   
Any thoughts appreciated. 

John

[Southside]

I am not familiar with the guide blocks that your mill uses but couple things come to mind when a band comes off the wheels.  What is the condition of the drive belt that the band rides on?  What about the other side?  When belts wear the band will contact the drive wheel and break, fall off, push back, etc.  What is the tension setting on your band?  A loose band, or one heating up will expand and fall off too.  Just a couple of things to look at.  

[KenMac]

It seems that I remember something about over lubrication was causing some similar issues. Search may find these posts.