On tough moving bolts like that I use a Mapps or propane tourch to heat it real hot and then spray penitrating oil on...that will beak the rust on the threads loose and some oil will lube the threads. You may have to do it a couple of times if not done (hot enough) correctly.
The teeth on the back of the saw is called a sliver tooth...it's for cutting the slivers when they run the log back to take another cut. The guy sitting there is on his lunch break...ya think.
Philly...filer 38 years and don't miss the BS