Circular Sawmill Blade Tuning

Large circular sawmill blades are hammered to dish the blade when at rest; it flattens out when the mill is running. Here's more. April 30, 2009

Question
I am trying to find out what the best rpm is to run a 54" sawmill blade on my sawmill.

Forum Responses
(Sawing and Drying Forum)
From contributor S:
The folks that sell the saw blades have a feet per minute (fpm) ranges for their blades. This is true for circular and band blades.



From contributor Y:
I'm no expert on circular saw blades, but I believe they are "hammered" to run at specific speeds. It’s my understanding that at rest, the blades are somewhat dished or curved and when you get to the right rpm they'll "stand up" or get straight. Check with other mills in your area to locate an expert who works on these big saws.


From contributor D:
It should be stamped on the saw near the hole in the center. But then again it may have been hammered for a different rpm. Saws have the metal in the middle stretched (tensioned) a certain amount so that when they spin at the proper rpm, the centrifugal force equals the amount of tension and they run straight. The bigger the blade, the more important the rpm is.


From Gene Wengert, forum technical advisor:
A 54" blade will be curved when it is hammered for a specific rpm. It is not made for a specific speed, but is hammered for such a speed. A person who hammers the blade will have a long curved "straight-edge" that he puts on the blade to check its curve. On the mill I managed, we had a 54" that was set for 610 rpm, but it did not run very well, so we had it cut down to 48".


From contributor N:
You can put it on the mill and try different rpm’s till the saw "stands up". I have seen saws hammered for 350 to 850. The best and safest thing for any unknown saw is take it to a saw doctor. The saw is also hammered for a right hand mill or a left hand mill. When the mill is off the concave side of the blade should be towards the log.