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[email protected] etpm@whidbey.com is offline
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Default Why do bandsaw blades break?

On Mon, 14 Dec 2020 21:25:41 +0000, David Billington
wrote:

On 14/12/2020 03:18, Jon Elson wrote:
John Doe wrote:

Seems my DeWalt portable bandsaw causes blades to break prematurely.

The shorter the blade, the more revolutions per minute it makes over the
wheels. That constant straightening/bending fatigues the metal. My blades
usually break at the weld, showing that my blade welding is not as good as
it should be.

Anyway, a giant 6 foot tall saw ought to have blades that last longer than a
portable one. That's just expected.

Jon


Without having done the bending calculations I'm inclined to think the
stress in the blade will be well below the fatigue limit for the
material so should go around indefinitely without breaking. All the
blade breakages I've had had a root cause such as tooth damage which
results in the blade getting hammered in that area till it breaks. I
normally use Lenox bimetal blades and they seem to last well.


My bandsaw blades tend to break in random places. Once a blade breaks
if I examine it carefully it will show several places where cracks are
starting to form. These cracks usually are not associated with any
other obvious defects, such as broken teeth and are close to
perpendicular to the length of the blade. Broken teeth could be the
cause of some breakages but I hardly ever have teeth break on my band
saw blades. Usually the cracks will run the entire width of the blade
but of course they are not very deep. This makes me think that the
blades are very well made, very uniform, because there will be several
cracks just starting to form, all at about the same time.
Eric

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