slightly twisted bandsaw blade

[Brian Deakin]

Let me explain
I was using a 3hp bandsaw to saw a freshly cut cherry blank in half The log was 15 inches high and about 12 inches in diameter and I had cut about 7 blanks with no issues
On cutting the 8th blank the blade became pinched in the wood .I stopped the saw ,removed the blank with the blade pinched ,then using several wedges I removed the blade from the wood

My question
The blade was twisted in the process of removing it from the blank and also has a slight kink in
If you turn the blade by hand in the saw with no guides and view the blade you can see a periodic slight wobble at the back of the blade during each rotation
Do you think the blade is safe to use

The blade is a m42 2/3 teeth per inch and 30mm width (one and one quarter inches)

[andy bessette]

Remove the blade and straighten it on the bench before trying again to use it.

[Brian Deakin]

My initial thoughts were to recoil the blade to re introduce curvature and leave it overnight to relax . Then reexamine the blade, if there are any areas which are uneven , clamp two pieces of wood either side behind the gullets to apply even pressure and straighten that area of blade

Please note there are only about 4 small areas about 2 inches long to address

[Richard Coers]

My initial thoughts were to recoil the blade to re introduce curvature and leave it overnight to relax . Then reexamine the blade, if there are any areas which are uneven , clamp two pieces of wood either side behind the gullets to apply even pressure and straighten that area of blade

Please note there are only about 4 small areas about 2 inches long to address


Where did you get the theory that carbon steel will relax? It won't. Also clamping wood to the blade will not remove a kink. You'll have to do some hammering on an anvil to move steel. There is likely a stress riser where that kink is, and since the blade is so brittle, you will likely see a crack there soon. Some heat with a torch might help, but will soften the steel. Not necessaryily a bad thing since you will have lots of hard teeth still there. If you bend some bandsaw blades far enough, they break. You can't bend them much at all and get away with it. Buy a new blade, you are going to need it.

[mike ash]

I’m not bragging, but I have lots of experience with twisted bandsaw blades!!!! Therefore, I agree with Richard’s analysis and advice. Buy a new blade, and figure out what caused the problem so that you may reduce the number of similar events!!

[david privett]

buy a new blade then fool around which ever way you can with trying to get the kink out and save this blade for any questionable metal holding wood. That away if you hit something you are not out much.

[Paul Williams]

I repaired a half inch blade that I managed to kink by beating it out on an anvil. It worked, but I was never satisfied with the repaired blade. I vote for a replacement. Try to fix the original blade and keep it for questionable wood or incase you break a blade and do not have a replacement onhand.

[Brian Deakin]

Thank you to everyone for your replies I have concluded the blade cannot be repaired

I saw this link
https://www.leevalley.com/en-gb/shop/garden/garden-care/weeders/73258-garden-bandit-hand-loop-weeder
and I am planning to use the blade to make a hand weeder similar to the design in the link

[Alex Zeller]

You may want to experiment with a narrower blade with a wide kerf. I assume you were making straight cuts since that sounds like a resaw blade you were using. If so your blade could have been made to deal with kiln dried boards with a narrow kerf to avoid wasting too much wood. In green wood a thin kerf blade is more likely to get pinchd.

[Brian Deakin]

Thank you to everyone for your replies and advice
The reason for the blade failing was poor practice on my part which is inexcusable
I had cut 15 logs with no issues Log number 16 appeared to just fit under the cutting height of the bandsaw I did consider reducing the length of the log but decided no It will be fine
I cut 95% though the log then found the final 5% was about 1/2 a inch too long
I switched of the bandsaw and the blade became pinched in the saw curf
To remove the blade I had to take the blade and the log off the bandsaw and use metal wedges to release the blade During the process maneuvering the log the blade twisted

lesson learnt