Blades keep breaking on my bandsaw

[Woodworkingal]

Thanks Rick
I will try!

[wa2crk]

I am getting that you are using SS blades?
Did you set the bandsaw up correctly? Specifically, Are the blade backup bearings properly adjusted? The upper backup bearing should be about .100 behind the spine of the blade. The bottom bearing below the table should be set the same. If the bottom bearing is too far back and away from the spine of the blade then the blade will try to move to the rear and will contact the upper bearing as it should, but there will be no contact at the lower bearing. If this difference is too excessive then a lot of strain will be put on the weld as it passes the upper bearing. This MAY be a cause of premature weld failure. Try to get a mental image of the side of the blade with the teeth facing left and imagine what would happen if you placed the spine of the blade on a bearing and attempting to flex the blade rearward (the direction of a cut) and you will see how this would strain the weld.
Bill V

[JPG]

I am getting that you are using SS blades?
Did you set the bandsaw up correctly? Specifically, Are the blade backup bearings properly adjusted? The upper backup bearing should be about .100 behind the spine of the blade. The bottom bearing below the table should be set the same. If the bottom bearing is too far back and away from the spine of the blade then the blade will try to move to the rear and will contact the upper bearing as it should, but there will be no contact at the lower bearing. If this difference is too excessive then a lot of strain will be put on the weld as it passes the upper bearing. This MAY be a cause of premature weld failure. Try to get a mental image of the side of the blade with the teeth facing left and imagine what would happen if you placed the spine of the blade on a bearing and attempting to flex the blade rearward (the direction of a cut) and you will see how this would strain the weld.
Bill V

Gotta disagree here!!!

The upper backup bearing should be barely off the back of the blade(far less than 1/10 inch).

The back of the blade rides the lower backup bearing. That bearing also guides the blade onto the lower wheel the same as the rear guide bearing guides the blade onto the upper wheel. Only the upper backup bearing is adjustable in/out from the blade.

The blade guides should NOT cause the blade to deviate from a straight line tangent to the front of both wheels.

[wa2crk]

The two backup bearings are there to keep the blade straight during a cut. When the blade is not cutting it will run straight. When pressure is applied to the blade during a cut and the backup bearings are not equally spaced behind the blade stress on the body of the blade occur and the weakest point of the blade is the weld. My mistype should have been .010. The actual amount can vary but the upper and lower clearance should be the same. Is the lower bearing missing? Would not be the first one to go missing.
As I said the weakest point on the blade is the weld so look for a condition that would cause excessive strain on the weld. All of the normal stuff seems to have been done in the previous posts.
Or she just got a bad batch of blades.
Bill V

[JPG]

The two backup bearings are there to keep the blade straight during a cut. When the blade is not cutting it will run straight. When pressure is applied to the blade during a cut and the backup bearings are not equally spaced behind the blade stress on the body of the blade occur and the weakest point of the blade is the weld. My mistype should have been .010. The actual amount can vary but the upper and lower clearance should be the same. Is the lower bearing missing? Would not be the first one to go missing.
As I said the weakest point on the blade is the weld so look for a condition that would cause excessive strain on the weld. All of the normal stuff seems to have been done in the previous posts.
Or she just got a bad batch of blades.
Bill V

Well that makes more sense! However the blade does ride against the lower backup bearing(there be no way to adjust it), and is located to align the blade to the lower wheel. Since as you stated, the blade needs to NOT be stressed while cutting. The upper backup bearing needs to be closely aligned to the lower backup bearing. 0.010 is much better than '0.100', but even less and > 0 is better.

You may have hit upon the reason. Perhaps the upper backup bearing is either contacting the blade or is too far away from it. Not having ever run it either way, I have to assume that could be a cause(makes perfect sense).

I now be 'agreeable'.


Hopefully this discussion led to a 'fix' fer de workin gal up nawth and west.