vertygo

I have a weird issue with my bandsaw.

If I cut along a straight fence, the cut-line starts fine then basically curves outwards then will end up back the same distance it started at.

Just wondering what the cause of this is ? tension ? user error ?

woodnthings

This phenomona is call "drift" and occurs when the blade begins to dull and or has inadequate tension. Start with a new blade and back off all the guides after centering the blade on the wheels and applying the proper tension. Use the tension indicator or "thunk" the blade like a guitar string and listen for the sound. A dull, low sound indicates a loose blade. A clean higher sound indicates a proper tensioned blade. Increase the tension as you proceed to get it right. After centering bring the back guides up to the back of the blade so they just barely touch the blade, top and bottom. Next bring the side guides in to do the same. You can use a folded dollar bill to check the gap. Repeat for the bottom guides which are harder to see and get to. The saw should now cut straight using the fence with no drift. Inadequate tension is a major cause of drift and causes a "hollow" or curve in the cut. As the blade enters the work the forces cause it to "stack" the blade on top of the work reducing the tension, causing drift. A tight blade will resist these forces, unless the feed rate is too fast. Just let the blade do the work feeding enough to make the cut. Good Luck. bill
BTW sometimes the teeth on a blade will wear on one side or the other causing drift as well. Cutting curves in one direction only will cause uneven wear.

__________________
Never stand directly in front of a horse or tablesaw that's running!
If you're not making dust, you're gathering it. After I reread my own posts, I agree with myself even more.

wdkits1

Bill has given the proper procedure for setting the guides and the tension. I might add that when I install a new blade I round off the back of the blade with 100 grit sandpaper to remove the sharp burr that is present on all blades. This allows the blade to clear the cut without as much rubbing. Also you may find that the fence may have to be adjusted slightly out of parallel with the miter slot to prevent the blade from flexing. Always use a sharp blade.

__________________
Mike
www.midlothianwoodworks.com

Why buy it when you can build it

vertygo

Thank you both. I suspected it was drift, but of course I assumed it was a tweaking issue.. forgetting that the blade is very likely dull! Now to research a new blade (small projects, hobby use, etc)

Cheers!