Bandsaw Adjustment – How accurate?
Hastings
| Posted in Power Tools and Machinery on
Yesterday, I was adjusting my Laguna 16HD for drift. The instructions call for the fence to be adjusted until the blade is exactly centered and parallel to the kerf. I cut a test piece and measured the difference in width using calipers and it is about 1/128th off per foot. In other words a 4 foot piece would be tapered by a 1/32nd, etc.
Using the standard Mark I eyeball, the blade appears centered in the kerf and therefore within tolerances.
My sense is that this is “sufficient” but would be interested to know if anyone thinks it needs to be finer? And if so how would I do that?
Thank you for your help.
Hastings
Replies
I've never found it necessary to get too exact on drift adjustment. Band choice and sharpness is much more important. I don't have a lot of experience with bands 1" and up so if that's what you're using your mileage may vary.
I may not totally understand your comment though. If you're getting tapered workpieces when cutting with a fence, there's something wrong. Likely culprits would be the workpiece not being held tight to the fence or a table that's not perfectly square to the band causing you to get different measurements top-bottom.
Pete
Edited 2/11/2007 11:13 am ET by PeteBradley
The typical way to set a bandsaw fence for drift is to draw a line down the middle of a piece of stock, parallel to the edge, cut along the line (as if ripping the stock) to about half-way through, and then setting the fence to the angle the board lies at on your table. I don't know how one could "eyeball" a blade in a kerf and really get parallel close enough to adjust correctly for drift.
All that being said, you might be able to greatly reduce drift by tweaking your saw some. Blade must ride in the middle of the tire (top of the crown if the tires are crowned), be tensioned correctly, and be a sharp and quality-ground blade.
forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
Forgive me; I probably wasn't being clear.I have adjusted the fence as you suggest. If I then rip a piece of wood, it is "out" by 1/128th per foot. Should I make further fence adjustments? Or is this close enough? Say to resaw some cherry for bookmatched panels?Thank you for your patience!Hastings
Hastings,
Considering that you will have to joint the edges before you can properly bookmatch and glue them up, that should be more than adequate.
Hope that helps. If I'm wrong, some of you more experienced woodworkers jump in and tell us. I am constantly amazed at the depth and breadth of knowledge here.
SteveThere are two secrets to keeping one's wife happy.
1. Let her think she's having her own way.
2. Let her have her own way. President Lyndon Baines Johnson
I'm sure you're measuring a difference from one end to the other, but I wouldn't conclude that it's out by 1/128 per foot. It's not possible to get a continuous taper without passing the workpiece in at an angle to the direction of feed (which in this case is the direction of the fence). More likely you have some variation in the piece you made. As others mentioned, 1/128 is fine.
Pete
Pete:Thank you. Before I do any more adjusting, I need to cut some more wood to better assess if there is a problem.Hastings
Hastings, You've asked and answered your own question: Is eyeballing the blade in the center of the kerf accurate enough? Not quite. How do you know? The cut is off by 1/128" per foot of cut by your own measurement. That measurement is far more sensitive regarding the correct "tuning" of the saw. The proper position of the blade, as set by the upper wheel tracking adjustment, is on the very top of the crown of the tire of the upper wheel. At that positioning, the band (blade) is perpendicular to the plane of the upper wheel and parallel to the rip fence. But the "test" of the blade's position on the tire/wheel is the cut itself. Move the tracking adjustment, slightly, one way or the other until the accuracy of the cut is to the tolerance you need. 1/128" per foot of cut is not really bad but sounds just a little high if you are determined to get better results. It should be possible to get about half of that. But don't drive yourself too crazy. The bandsaw is not that much of a precision instrument in this regard. For instance 1/32" difference over 4 ft of resawing an 8" wide board would not be unreasonable, especially when planing out the saw marks. Rich
Rich:Thankyou, that was very helpful. I will do as you suggest and see if I can get a better result. I was not sure how good was good and now I know!H
I sort of thought bandsaw drift was a thing of the past. A few years ago, on a whim at a trade show, I bought a blade made from what I think was called Swedish steel. It was claimed to have no drift. I had a cheap tabletop band saw (Rockwell Beaver) at the time and the blade eliminated the drift. I now have a 14" no-name band saw with Swedish steel blades and again I have no drift. I just put the board against the fence and puch it through the blade. The instructions for the blade indicate that it requires very little tension and that also seems to b e the case. I assume Swedish steel is well known, it seems to be bought in bulk, made into band saw blades and resold by many firms.
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