Mystery Sawmill Part

[ncsawyer]

I started the mill Tuesday evening, and after letting the mill idle a minute, I heard a "tink" sound.  When I looked, I saw this small piece of cast aluminum hit the ground.  I assumed it was a small piece of the alternator or starter, but could never find where it came from.

Finally, I took the cover off of the alternator, where the idler for the alternator belt is.  It was a piece that broke off the idler.  Seems to serve no purpose, since it still keeps the belt tight.  But I wonder what would cause it to just decide to break.

[Brad_bb]

...flaw in the casting, and after enough vibration and heat cycles....?

[FloridaMike]

Looks like that the broken piece engaged the spring loaded pin, which is now being engaged by the remaining casting.  Still will work, just very slight reduction in spring tension.