Bandsaw Drift and Correcting It

I posted this elsewhere but then realised I should have put it here as drift is a common problem and it need not be.. To read it in context look at this link

https://www.woodworkforums.com/f187/surprise-225034-post2150069#post2150069

I had a play tonight with my saw and did what I have recommended to Fletty and a few other people having trouble with their saws. I put two rare earth bar magnets on the blade and then stuck a 600mm steel rule to those, the magnets have to be clear of the teeth otherwise they won't be flat on the blade. I locked the fence to the rail and loosened the trunnion bolts to swing the table around but there was not quite enough movement and it left the fence still not parallel to the rule. European saws work a bit different to the generic Asian/US saws in that the tracking does not have the same adjustment as the Asian versions because the teeth have to hang off the side of the top wheel and the only function the tracking does is to get different width blades to that position. On my saw they have allowed for that and a fence adjuster can be seen in the photos and this aligns the fence to the blade. On an Asian saw the tracking would be changed if the table movement is not enough. Make sure all the guides are set in the running position with correct clearances also.

When I first set it up I looked at it and thought it was practically spot on until I measured from the rule to the fence and found about 20mm difference end to end and this had been doing a lot of resawing with no issues. It will be interesting to see what it is like when I do some more. I used the adjusting bolt and now it is spot on.

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Good one - thanks for posting.:2tsup:

My BS does adjust for drift using tracking, but this is still a useful way to zero in on the correct position. Take magnets/ruler off, run saw for a minute so that blade settles down in new position on the wheel, reapply magnets and ruler, check against fence, adjust tracking position, rinse and repeat.

I'll be interested to see if cuts are actually drift-free when this method says that perfect alignment to the fence has been achieved, or are there any other factors at play? Obviously the blade will have to be at working tension when doing this.

A blade that is poorly sharpened or perhaps has more set on one side or another will encourage drift. There was a batch of 25mm Resaw King blades that had been poorly sharpened when they were first introduced here that did this due to being badly made.

You can also correct drift by adjusting blade tracking; at least on bandsaws with crowned wheels, I've never had a Euro saw with flat wheels. In my experience this matters more with larger width blades, which is what you are using for resawing.

If the fence is parallel to the mitre slot the big advantage to moving the table ensures that the mitre slot has the same relationship to the blade as the fence.

Bandsaw Tips: How to eliminate drift from your cuts

Quote:

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Originally Posted by Chris Parks

If the fence is parallel to the mitre slot the big advantage to moving the table ensures that the mitre slot has the same relationship to the blade as the fence.

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To take this a bit further a cross cut sled can be used for accurate cuts if the mitre slot is parallel to the blade. I made one and it is damned useful especially for small pieces.