Blade Drift on Band Saw?

[Tommy Emmons]

I have seen references to blade drift on a band saw and that you need to adjust the fence to compensate for this problem. Can someone explain what cause this and how do you align the fence to compensate? thanks Tommy

[Lance Norris]

Tommy, bandsaw blades rarely cut straight when ripping. To adjust the fence for drift, draw a straight line on a board thats 16-24" long. Cut, following the line about 2/3 the length of the board. Stop the saw and dont move the board. Draw a line in pencil on the bandsaw table against the edge of the board. Remove the board and align the fence to the line you drew.

[Jim Dunn]

Lance would blade drift adjustments be the same for resawing? It seems like the more blade you have in the wood the blade would or could act differently. Make any sense?

[Brad Schmid]

My experience has been that blade drift has depended on 3 things:
-saw design : crowned tire design vs flat tire design
-tracking: blade tracking too far forward or back on a crowned tire
-blade design: specifically tooth set and how accurate the set is (right opposed to left)

My 14" saw with crowned tires and a timberwolf blade has big drift.
My MM16 (flat tire) with carbide trimaster (no tooth set) properly aligned has no perceptible drift.

YMMV
cheers

[Howard Acheson]

I would respectfully disagree with you Brad. There are really only two factors that affect blade drift. One is the position of the blade on a crowned tire and the second is the blade itself.

A blade should be adjusted to run on the center of wheels that are coplanar. Once a blade moves away from the center of the crown, the blade will want to drift one way or the other.

The condition of the blade is the second factor. If the blade is properly sharp and the teeth set is good, the blade should cut without drift. Generally when a blade begins to drift, it is because the blade has been damaged or it has become dull unevenly. It either event, a new blade should fix the problem.

I have a 14" bandsaw with Cool Block guides. It tracks perfectly in the center of the tire and it cuts exactly parallel to my rip fence with my 1/2" wide resaw blades. If it begins to drift, I look to either the blade position on the tire or to the wear on the blade.

BTW, the amount of drift should not be dependent on the thickness of the stock being sawn.

[Lance Norris]

Lance would blade drift adjustments be the same for resawing? It seems like the more blade you have in the wood the blade would or could act differently. Make any sense?

Jim... I have several books on bandsaws. They all describe the drift adjustments as I stated. They dont really say anything different about resawing. I wont say that drift isnt different, or a problem in resawing. Thats why some bandsaw fences come with a resaw post instead of a high fence attachment. I havent had much trouble with drift on my bandsaw that I use for ripping and resawing, so I dont really have any comment from experience.

[Stan Urbas]

OK, these might sound like conflicting messages, but in fact they aren't. First of all, keep in mind that:
- if your blade is not sharp, there is no way you can control drift.
- you should push your work into the blade easily; if you force it, causing the blade to bog down, you'll cause drift
- If you are sawing very hard wood with a wavy grain, especially close to a knot, the blade will tend to follow the grain. If so, ease off a bit.

Now as to alignment. Any blade can drift a bit, even if well-positioned on the crown of the wheel. Go back to Lance's first post. It is the correct way to align the blade to the fence, even if the blade is a little bit dull or not perfectly positioned on the wheel. But you have to re-do it every time you change blades or change the angle of the wheel.

The only thing that I would add to Lance's post is that following his procedure should only result in a small adjustment in the fence. Any more indicates that the blade is not on the center of the wheel.

[Rick Levine]

Like Howard I also have cool blocks and I also replaced the bearings with the cool block material and with a good sharp blade on my Delta 14" BS I have very little drift. My saw is an older US made version and I'm not sure but that may be a factor also. One further thing I did was replace the tension spring with an after market one and that may also help.

[Brad Schmid]

I would respectfully disagree with you Brad. There are really only two factors that affect blade drift. One is the position of the blade on a crowned tire and the second is the blade itself.

A blade should be adjusted to run on the center of wheels that are coplanar. Once a blade moves away from the center of the crown, the blade will want to drift one way or the other.

The condition of the blade is the second factor. If the blade is properly sharp and the teeth set is good, the blade shown cut without drift. Generally when a blade begins to drift, it is because the blade has been damaged or it has become dull unevenly. It either event, a new blade should fix the problem.

I have a 14" bandsaw with Cool Block guides. It tracks perfectly in the center of the tire and it cuts exactly parallel to my rip fence with my 1/2" wide resaw blades. If it begins to drift, I look to either the blade position on the tire or to the wear on the blade.

BTW, the amount of drift should not be dependent on the thickness of the stock being sawn.

In hindsight, I agree with you Howard and I worded that poorly. What I was attempting to convey with my comment about saw design was that depending on design there are different factors to consider when analyzing a drift situation. As you say with the crowned tire, it should be aligned to track at/near the center to avoid skewing the blade, on the flat design tire, that is not the case.

cheers

[Jules Dominguez]

I use a homemade fence for re-sawing, made of two 5" or 6" wide pieces of 3/4" MDF glued at right angles.
I mark my resaw line on the edge of the first workpiece (or on a piece of scrap of the same wood, width and thickness) and feed it into the blade freehand, adjusting the direction of feed to compensate for drift and stay on the cut line. After I've cut far enough into the workpiece that it will stand unsupported on the table, I stop the saw, set the fence up against the workpiece and clamp it to the tabletop with two 6" bar clamps.
I then finish the cut in the first board and carry on cutting as many other boards as needed. Subsequent cuts are made holding the workpiece against the fence and it doesn't drift. This extra step of aligning the fence to compensate for drift takes very little time. It's simple, it's easy, and it works. It's not my original idea, I read about it many years ago.
My bandsaw is a 1982(approx) 14" Rockwell with all original fittings, no "special" guide blocks, tensioning, or tuning. No riser block. The blade's probably not centered on the wheel, but the drive belt is a link-belt and the pulleys are in alignment..
I use 1/2" 3tpi "Timberwolf" blades for resawing.

[Pete Bradley]

More often than not, what people perceive as "drift" is the result of a dull/damaged band, a band with too many TPI, or one that is poorly tensioned or too wide. That's not to say you never have to adjust for it, but likewise you can't adjust away a bad band. You don't need cool blocks or aftermarket springs to control drift.

3/32" veneer sliced from 12+" green ash log. Steel guide blocks, stock spring, stock 1HP motor, 1/2"X3TPI Timberwolf band. No drift adjustment, run straight down the miter slot:

http://home.comcast.net/bandsaw_mythbusters.JPGhttp://home.comcast.net/%7Ebradlzz/bandsaw_mythbusters.jpg

Pete

[Wayne Cannon]

Well stated.

In addition, blade teeth are not always the same on both sides of a new band saw blade. Some blades are stamped. Some are not sharpened identically. There are several brands/models (Timberwolf, WoodSlicer, etc.) that are fabricated more uniformly -- e.g., with ground teeth instead of stamped teeth.

In my opinion, that doesn't necessarily make them better. They just contribute less to blade drift, which is easy enough to compensate for anyway.

[Chris Padilla]

3/32" veneer sliced from 12+" green ash log. Steel guide blocks, stock spring, stock 1HP motor, 1/2"X3TPI Timberwolf band. No drift adjustment, run straight down the miter slot:

Pete

Well, the end-grain of the ash log is certainly GREEN! :D
Now whatcha doin' cuttin' veneers from plain old boring old ash?! :confused:

;)

[Pete Bradley]

Now whatcha doin' cuttin' veneers from plain old boring old ash?! :confused:


That particular cut was just a demo while cutting up an ash log into mallet blanks. I like the picture because it's an example of how many elements of bandsaw "internet wisdom" don't necessarily hold true.

I have used these sheets in the past though. For example I sliced one into strips and steam bent them into toy toboggans that were used to decorate a Christmas tree for a charity auction.

Pete

[Chris Padilla]

Sweet...and a sweet cut on the log, too....