Jumping bandsaw blade

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Hi guys.

I've changed and adjusted properly ( or so I think) the blade of my bandsaw, it cuts OK but it jumps from time to time.

Are there any further adjustments or checkings I could do to avoid this?

I've checked the wheels alignment, the blade verticality in x and Y axis, the blade tension. I don't know why is this happening.

Any help will be greatly appreciated.

Many thanks in advance.
 
Yes, some further description of the "jump" would help. Are you saying that the blade runs along normally and suddenly moves forward or backward in relation to the direction of cut? Is is a "jog" like the blade has caught on something while in motion? Inquiring minds want to know ;-)
 
We definitely need more clarification. Do you mean it bounces once every time it goes around (indicating a poor weld), or does it suddenly shift position frontwards or backwards, or does it leap off the wheels, tearing at the covers & exercising your puckermuscle?
 
Often caused by the weld..

Sometimes rounding over the both sides of the back of the blade with a stone will help. If the teeth don't match up properly at the weld there isn't much that can be done to help that blade. Save for rougher cuts...?

Garry
 
Yes, some further description of the "jump" would help. Are you saying that the blade runs along normally and suddenly moves forward or backward in relation to the direction of cut? Is is a "jog" like the blade has caught on something while in motion? Inquiring minds want to know ;-)

Thanks guys, the way Glenn describes it is the most close one, the saw is cutting smoothly and all of a sudden it makes a short shake as if it had caught a silica deposit in the wood or something harder within the wood.
I neither have checked the weld nor the teeth, so I do not know if they are OK.

I'll do it asap.
 
Remove the blade and look for kinks. Or a crack in the weld. OR Open the doors and turn the wheel by hand and watch the blade go through the upper guides... at the instant of the "jump" you will find the cause.

Physics of the BS is so simple, The blade is usually the culprit... Seldom problems like a chunk of trash on the wheel, bearings wornout, improper set-up.

I must ask, Did you back off all guides & bearings (upper and lower) when you installed the new blade? If the answer is No then you didn't do a proper install as no matter or not if you used the exact same brand, design or size blade, every one is different and has to be tracked w/o the guides and bearings in play, then move them into hold the alignment not to create the alignment. This may be what is happening...

If it just started when you changed blades, it is either the blade or the procedure that is to fault.
 
Remove the blade and look for kinks. Or a crack in the weld. OR Open the doors and turn the wheel by hand and watch the blade go through the upper guides... at the instant of the "jump" you will find the cause.

Physics of the BS is so simple, The blade is usually the culprit... Seldom problems like a chunk of trash on the wheel, bearings wornout, improper set-up.

I must ask, Did you back off all guides & bearings (upper and lower) when you installed the new blade? If the answer is No then you didn't do a proper install as no matter or not if you used the exact same brand, design or size blade, every one is different and has to be tracked w/o the guides and bearings in play, then move them into hold the alignment not to create the alignment. This may be what is happening...

If it just started when you changed blades, it is either the blade or the procedure that is to fault.

Thanks Bill, each time I change a blade I make a complete general adjustment, that's why this is puzzling me. I have to recheck the blade and the weld as suggested, most problably there lies the problem.
 
Try checking the wheels to see if the adhesive is secure all the way around. A long time ago my dad's bandsaw was having the same problem. I think one of the wheel tires (rubber) had become partially unglued and was occasionally bunching up causing the bump. I don't recall if it was the top or bottom wheel.

Cheers,
 
Sometimes a splinter will drop through and get caught between the wheel and the blade; it goes arond once and pops out the other side.

I have another hair-brained theory to describe an accasional "chattering" effect: I think there occurs a random phenomenum where the teeth line up synchronously with the grain pattern of the wood and simulate the "washboard" effect; the teeth sinking into the soft wood like gears.
Like I said: it's a theory.
 
Hey William, I've not seen you in a while, hope you are well!

Toni, I cannot add to the good advice given, the few times I've had trouble, changing the blade solved the problem. :thumb:
 
I just went through the same thing. A blade change solved the problem. But as always, there is more to the story. My saw is a Shop Fox.

I didnt have another 93" blade because I bought the saw with a riser kit so it will cut up to 12". So, in order to change the blade, I had to install the riser block. With a little help from my dad, we installed the riser block. The blade tensioning is much better now with the longer blade and the riser block.

The only reason I can think that the tensioning system works better is the 105" blades are the correct length and the 93" might have been a tad too long.

My uncle has read a few articles where people have been having issues with 93" blades and have found the blades are a little bit too long. The blades have been manufactured out of specification.

The original 93" blade was terrible for tensioning. The second 93" blade was OK, but still not great. Once I went to the 105" blade, all the problems went away.

I thought about putting a shim between the seam of the upper and lower frame sections where the riser block goes, but to do that, I might as well install the riser block. A person should not have to shim the frame to make a blade run correctly.
 
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