Does adding an extension to a band saw cause drift

The longer the blade, the more critical proper tension seems to be… The OEM tension spring in most 14” band saws is barely adequate. If you install a riser block kit, make sure you spring a few extra bucks for an upgraded tension spring like the Iturra, or Carter springs. I have a Carter in mine and drift is a non issue…

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Strange to me how a spring could make a difference. They are only $20. Done

It certainly can.
When you add an extension you realigh the angle of the top of the saw. How much you mess with it is unknowable.
Onve you point the upper guide off in some other direction you will get something that looks and feels like drift. But it’s not.

What it is is simply the guides holding the blade at a new angle.

Drift s when the blade cuts to one side.

You can work on the upper body and try to re align it.
I’d start by looking at the wheels as the guide.

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Another data point:

I put the riser block on mine. Couldn’t tension well enough with 1/2 in blade. Added Carter Cobra spring. Problem solved.

As cr1 said, it is not really drift but rather a cupping of the blade as it flexes when feeding wood. I don’t think the frame alignment is really the problem though. It used to be a lot bigger problem. Especially with more “economy” bandsaws. I think that problem is mostly a thing of the past… or I have just been lucky. Even the cheap saws have better machining now. My HF was dead on when I installed the riser and didn’t have to adjust the wheels. (It has tracked perfectly since day one.) I don’t even remember having to readjust the guides.

The Wood Slicer blades I have not had as good of luck with. I tried one but it didn’t cut more than ripping one red cedar 2×4 before giving out. The Timberwolf blades have been consistently good to me. Other people swear by the Wood Slicer. I might have just gotten a bad one. I didn’t even bother complaining to Highland Hardware as they have always been so good to deal with.

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I might add that when installing a riser block it is very important to check co-planer adjustment. That is the position of the wheels edges being on the same plane.
My experience with drift generally boils down to blade quality and tooth set. My set up for resawing is not a fence per se but a round guide that is opposite the blade. This allows me to compensate for drift. My old saw has pretty good luck with maintaining plus or minus .010 for all four corners on a 10 to 12” piece.The thinnest I will saw to is approx .060” and then finish dimension with a drum sander.
tom

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This forum is great!
Thank you all.

Make sure the wheels are coplaner before doing anything else. Cast iron may feel hard, but it will flex if you tension the blade too much. Better to use a smaller blade (1/4”). A 1/2” blade can’t be tensioned with the existing spring and changing to a stronger spring can cause the iron to flex out of alignment. Blade drift is controlled by the blade guides, but guides can never be perfectly aligned. As long as there is any clearance between the blade and the guide (just a few thou’s), the blade will deflect. Skewing the fence a few degrees will compensate for the drift. The Mark Duginski book on bandsaws will tell you all that you want to know.

Drift is a weird but fixable thing. adding an extension will cause it to drift but drift is something that is distinct to each blade you use. Easiest way to account for drift is take a long piece of stock and make a line down the middle (2×4’s are easiest).. Cut free hand for about 6-8 inches then take an angle gauge and take the angle with the table as your reference. Then continue cutting free hand down the line and then check the angle at different points verifying it is remaining constant. Once cut take your angle gauge and adjust your fence to the angle. Once completed you will be perfectly parrallel with your blade. Plus the bonus is the drift will last the lifetime of the blade and will not change unless you make a change to the saw. This tip was featured on Wood Works with David Marks on how to adjust for Drift when setting up the bandsaw.

-- Drew -- "I cut it twice and it's still too short!"- Rock-n H Woodshop - Moore, OK