How do you determine how fast to saw a log? how fast is to fast? RPM's? Mill shaking? how do you know....any advice would help.
It's more of an art than a science for sure. It depends on the log species to start with, if it's green or dry as to where I think I want the speed to be. Harder and dryer, or twisted grain - going to be slower. Another big consideration is how knotty do I think it is, more knots then again it's going to be slower. Once I have an idea of where to be I listen to the mill, I like to keep it right on the edge of the governor so she is pulling hard, but not bogging down, I also keep an eye on the portion of the blade I can see by the movable guide, if it begins to dive I need to back down. Another good indicator is your band tension, if she is getting hot (dull, too fast, not enough lube) then the tension will begin to decrease. My right hand basically never leaves the speed control so I can instantly back it off if I need to.
The way I figured it out, go as fast as you can until something you don't like happens, like the blade starts cutting wavy, pushes itself off the bandwheels, or you stall the engine..and yes I have stalled the 55hp diesel on my super 70 lol...once you figure out at what speed something bad happens, then you can back it off just a hair and keep it just out of the red zone.
That to me is the best way to figure anything out...rather...the way I figure stuff out lol
When the carriage is shaking and your engine begins to bog down that means you are feeding to fast, and it may just happen in one part of the log. I also like to watch how much sawdust is being is being ejected from the cut because the blade needs enough time to properly eject enough sawdust so that it doesn't pile up under or over the blade causing it to rise or dive in the cut. I also keep an eye on the blade to see if it is diving, that's a good time to slow down too.
On a circle saw mill you are to feed as fast as you can and gig back fast also. In a perfect world you would feed until the gullets can't take any more sawdust. The teeth last longer if fed fast and on the return the log side tooth corner doesn't out wear the board side corner so much. It takes a really good mill, a good saw and plenty of power.