I didn't want to hijack a thread so I started a new one. Here is a short version of the situation as I see it.
Some Saws JustScream On Some Machines
It does not happen very often.Nobody likes it.It really is not anybody’s fault.
Sometimes a good saw shop can retention the blade and solvethe problems.Maybe once every year ortwo we sell a blade that screams and we just replacement them.
Good saw blades are tensioned so that they run straight andtrue.In saw blades the inside and theoutside a blade run at the same rpm but the outside covers a lot more distanceso it runs faster.This gives the bladea tendency to curl over which is highly undesirable for a variety ofreasons.A tensioned blade will use theinherent and/or induced tension in the steel to counter the tendency to curlover.
Because of the quality of the steel and the tension, theybehave somewhat like a tuning fork.Ashard as the industry tries it is so far impossible to make every bladeidentical.Currently, thestate-of-the-art is at a level where the problem is that no two pieces of steelare identical just as no two places in the same piece of steel areidentical.
Every machine is slightly different.Every machine has a different vibrationalfrequency no matter how slight.
When the right blade is put on the right machine then youget screaming because the frequency of the blade matches the frequency of themachine.
You can change the frequency of the sawblade with slits orslots or scrollwork or copper plugs at the end of the expansion slots and thatmay work.
You can change the frequency of the machine.About the only practical way to change, thefrequency of the machine is by altering the shape of the blade guard.Some guards actually have a little slidingdoor in them somewhere.Typically, theoperator has no idea what the door is for.
One way to test this is to remove the saw guard, run themachine, and see what the noise level is.This is purely for testing.Youdo not want to run the machine without a guard for any reason.Running this particular test can give theoperator the idea that running the machine without a guard is a good idea.
Sawblades have critical speeds.When a saw blade hits a critical speed, itwobbles.Sometimes it is just a plainwobble.Sometimes it is a morecomplicated wobble and this is called ‘potato chipping’ because the blade sortof looks like a potato chip in slow motion.Once you get past the critical speed, the blade straightens out untilyou hit the next critical speed.
Reply With Quote