There’s a very basic principle that applied to a band saw problem I just fixed. But whether the rule came from Holmes or Occam, I don’t recall.
I couldn’t figure out why my band saw was losing power. It cut fine in light wood of small dimensions, but bogged down seriously in thicker hardwood, the blade almost slowing to a stop at times. I checked everything – blade sharpness, tension, guide wheels and posts, etc. – and nothing remedied the issue. After exhausting everything I figured the motor was going bad.
Well, that happens. I’ve never had a motor go bad in decades of woodworking, so maybe I was due. However, it still cut when needed if I didn’t mind going slow, and since the extra cash wasn’t readily available for a new motor I just decided to live with it till it was.
Then the other day as I'm preparing to do some resawing, it occurred to me that maybe if I changed the saw to the slower speed (if it wasn't on the slower setting already), the drive belt being on the smaller pulley might give it more torque, and thus a bit more power. So I open it up to change the speed and discovered that the drive belt was flopping around in the breeze, barely making contact with the motor-shaft pulley. There was literally no tension on the drive belt; how it had been driving the blade at all is a mystery.
The thing of it is, is that I had checked everything I could possibly think of to check, so how I missed the simplest one is just as big a mystery. I can only imagine that as I went through all the potential causes that I just assumed I had already checked that one first and went on to the next. Had I written them down as I checked it might have been obvious which one I missed, but I didn’t.
The fix took all of two seconds, of course: I tilted the motor as needed to put some tension on the belt, locked it down, and the saw was zipping along at full power again. The solution could not have been simpler. Too bad the investigative procedure I employed wasn’t.