jowersjc

Sorry about taking so long to reply. Yes and no about the large round saws. We do have them but we do not work on them. Not enough room..! The de-barker on the yard end of the mill has two crosscut saws roughly 6' in diameter that cut the logs to length before they get sent to the bandmill. I was expecting it but it still comes as a surprise that I am learning something new it seems every day now that I have a new co-worker that worked at the same mill in the 70's when it was owned by International Paper. Now if we could only get rid of the one that "thinks" he's the head filer.

Sorry about that, 110 plate...

The best way I can think of to explain a bad dish in a saw is to think of a satellite dish. When a saw is heated to the point of bending, and a cant runs through it, the saw is going to dish away from the largest part of the cant. At this point, most if not all of the tension making that saw stand straight up and down is now in the lower section of the saw (tight in the eye), causing the outside to bend almost as if the metal is trying to curl up. Tension is a mysterious thing... I will try to get a picture of this somehow, it would definitely make more sense.

This is my first time posting so pardon me if I accidentally screw up a thread... I work at the Coushatta, Louisiana location of Idaho Timber Company as a Circular Saw Filer. This is more of a clarification than a disagreement on leveling round saws. A small diameter saw (19") with a somewhat thin kerf of say, .0110 plate thickness definitely needs tension in order to stand up straight in a cut. If the saw is too loose it will heat up and dish out one way or another causing problems for the rest of the saws on the arbor, depending on the machine you're running. A larger saw (24" diameter) with a thicker kerf will need to be tighter or stiffer and have less "fall out". What I call fall out is when you lay a saw flat on your anvil, put a gauge from gullet to gullet across the middle of the saw and lift up on one of the edges of the saw where your gauge is sitting, the saw "should" fall out all the way across evenly and on both sides. I believe this is what Jeff was referring to saying a saw needs a dish in order to run correctly. Centrifugal force causes a saw to stretch when it starts spinning, so when running a higher rpm, you would need more fall out than on a low rpm. The problem I have is getting the tension the same on all of the saws I work on. I don't have any tension gauges so I have to eyeball the drop from the gullet to the eye and roll tension in or out as needed. Hope I helped explain this a little. I would love to hear any constructive criticism if there are any filers out there.