# Band saw suddenly started to pull to one side



## bager (May 6, 2017)

Hi,
I've been quite happily using my new PorterCable PCB330 bandsaw in a couple of projects, it was working perfectly with almost no blade drift at all.
Then, very suddenly, it started to always go to the left. I don't think this is regular drift. Even when I adjust the angle to compensate for what would be usual drift, it still pulls to the left rather strongly, always ending up with ruined piece of wood.
I thought this could be due to bad adjustment of the guides, but spending some time to adjust the guides very carefully, did not help either.
Then I thought it might be dull blade. So I got a brand new blade, a 1/2" Vermont which is wider than the stock 3/8" (because these projects I am doing here, use only straight cuts).
This did not change anything -- the saw always pulls to the left. I am out of ideas as to what can be causing this. I inspected all parts that I could think of, and nothing appears wrong. Does anyone have a suggestion what to look for to diagnose this further?


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## woodnthings (Jan 24, 2009)

*You need to do a tune up*

If you are certain nothing has come loose, like the upper wheel assembly for instance ....then follow this video exactly by first removing the table:


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## bager (May 6, 2017)

Thanks for the explanation woodnthings!
I do understand what you say about good, specific questions. The problem is in the beginner's ability to formulate such a question. I suspect the problem with the saw itself is something easily identifiable, and if I knew enough about saws to ask the question up to your standard, I guess I wouldn't even need to come asking for help with the saw in the first place.
Well, at least now I can grab onto *some* starting point. I did look at the upper wheel assembly as one of my initial diagnostic steps, and was somewhat surprised that turning the tracking knob towards the more loose direction allows the wheel to tilt withing an increasing range of angles. I don't know how it is *supposed* to work but I figured this would be its normal principle of operation: the wheel just leans against the tracking regulator under the tension of the blade.
But then, if the wheel is indeed supposed to tilt freely back and forth (it also tilts about 1 degree left and right, which I suppose I can describe as "loose" but I don't see what one can do to tighten it, because there is nothing to adjust between the sliding bracket and the body of the saw and there is just a natural gap about 1/16" on either side), the first question is: how does one verify that the upper wheel assembly is not loose? what should be tight?
The second question is: what else must be checked for loose, other than the upper wheel assembly?


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## woodnthings (Jan 24, 2009)

*We are trying to isolate the problem by .....*

By starting with the obvious, like a new blade we then move on to guide adjustments AKA tune up. From there we go to major issues like wheel alignment. It should freely tilt in the wheel's face plane, but not tilt from side to side. This will cause the blade to track weirdly. 
Usually the sliding carriage moves up or down in rails like a drawer slide. See if you can wiggle the wheel from side to side and how much it moves in total. I'll check mine to see what I get.... I'll be back..... :wink2:
Well mine went from essentially zero, to about 1/32" on the 14" saws and about 1/16" on the 18". This is overall or total left to right play.

It is certainly possible your "new" blade was welded improperly and has a built in drift OR the teeth are slightly dull on one side. Look at them with a magnifier and see what you can tell. Other than all the above I'm out of ideas. The bottom wheel is fixed , so I didn't consider that. You do want the blade to track with the gullets in the center of the upper wheel regardless of where they fall on the lower wheel per the advice in the video.


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