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Bandsaw Fix won't cut straight blade drift

Believe it or not, it’s the nature of a bandsaw to drift either left or right of being perfectly parallel with the bandsaw fence.  It doesn’t have to do with the quality of a bandsaw. But it’s not necessarily the quality of the blade, either: if you swap the bandsaw blade with a new quality blade, the only thing that changes is the angle at which the blade drifts. Rest assured, it still won’t cut straight with the fence. Being a happy bandsaw owner (and user) has a lot to do with your approach to coping with the fact that a bandsaw simply will not cut straight, or, in the sage words of veteran woodworkers, “adjusting for drift.”

The trick is in adjusting the fence, not the blade.

powermatic bandsaw fence

The Powermatic 14" bandsaw uas 4 bolts on top of the fence. Use these for adjustment to make the saw cut straight

While adjusting for drift is a process you’ll have to do every time you change the blade, it’s a very quick and painless exercise as long as your fence has some adjustment to it. And it may not be obvious. Even the top performing 14″ bandsaw on the market, Powermatic’s 14 Bandsaw 1791216K, comes with a no-frills fence with 4 bolts on top rather than easy and obvious thumbscrews or knobs that say, “Adjust me here!”

The tried-and-true method to adjusting for drift goes like this:

  1. Take a board about 20″ long and mark a straight line along the length, parallel with (and about an inch from) the edge of the board.
  2. Turn on the bandsaw and begin to cut that board, following the line as perfect as you can (note: freehand, not with the fence.
  3. Stop the cut about halfway through the board
  4. There’s your angle. Using a pencil, trace the edge of the board on the table top
  5. Adjust your fence to match the line you drew on the bandsaw table. Now the fence is aligned to cut straight with that blade set up

Our demonstrator, Joe, came up with this auxiliary bandsaw fence that uses his factory bandsaw fence that didn’t have any adjustment to it.  Making the bandsaw cut nice and straight with this fence is a snap. The only tool required for adjusting is a screw driver.

Materials Required:

  • 1 x 4 hardwood suitable for new fence.  Length slightly longer than bandsaw table width.
  • Round Head Machine Screws –  2pcs –    ¼” x 20 x 1 ½”
  • Flat Washers –  2 pcs  –    ¼” flat washers
  • Dowel –  3/8”  approximately 4” long

Making the Fence:

  • Cut 1 X 4 material slightly longer than bandsaw table width.
  • With router cut a shallow channel across wooden fence approximately aligned with the bandsaw blade.  Use ½” core box bit
  • Use 7/8” forstner bit to countersink screws in face of wooden fence
  • Drill wooden fence with 9/32 bit for screws
  • Mark holes on factory fence
  • Drill and tap factory fence to accept 1/4 x 20 machine screws  – drill with 7/32” bit and tap with ¼ x 20 tap.
  • Assemble with ¼  X 20 X 1 ½” screws through fence with dowel in the groove.  Note:  dowel could be glued in place, but I chose to keep it loose in case I want to use a smaller or larger dowel in some situations.

auxiliary bandsaw resaw fence fixes drift

 

 

  • Michael Nestor

    Seems like a ‘teach yourself’ kind of thing. I struggled with a band that was made by Magnate. I did a lot of resawing with it. But when it broke I bought a timberwolf. I was able to to cut 50 foot of 8″ oak, (add some more foots for the offcuts), no problem. I finally realized my dream and all the work I had put into making my resawing sled. Untill today. The damn thing starts cutting to the left, not immediately, 4 feet into the board. But this is the price I pay for maxing out my saw. But you should see my lumber. You can’t buy this kind of lumber. I am thinking about doing a co-op with neighbors on that HF resaw machine. Now I get to go back out there and start troublehooting again. A new cut today, starts fine then the blade bows inward and puts too much stress and the blade is dragging through the cut.

  • blackbeered

    I came here wanting to know “when will the drift angle change”?

    When I change the blade, whether it be newer, finer, coarser, wider]? When I change the blade’s tension? When I change the blade’s tracking?

    I didn’t get any answers to those questions.

    • The short answer is yes. It can change under any of those conditions. The change may be slight, or not.

      • blackbeered

        Thanks … I better keep a dumpster full of ‘calibration blocks’.

  • Eric chapp[e

    my bandsaw will not cut straight even freehand it takes extreme right hand turn and two different blades

    • Need more info to give you better help, but you might have improper tension on the blade and/or guides, misaligned wheels, worn tires, etc, etc.

      • Lo Tech

        Same here – please can you explain why ” improper tension on the
        blade and/or guides, misaligned wheels, worn tires, a bad blade, etc,”
        might cause drift. My blade drifts without or with fences however I set
        them up. Can you give a better reason: something I can adjust and try
        out (maybe not the tension which is easy to try – also tried guide
        alignment)? This happens even in homogenous materials;
        even thin mdf.

        • Let’s back up. The reasons for a bad cut can be dozens. So, by “need more info” we need know the basics before offering a shotgun blast of suggestions. Is the blade new, is the saw new, how do the guides look, etc, etc, etc.

          Have you stepped through the basic set up of the saw? This is a good overview if you haven’t done it yet. Basically, this covers “what to adjust”: http://www.finewoodworking.com/tool-guide/video/how-to-set-up-a-bandsaw.aspx

          Start with the simplest solutions first. Verify the blade is good. Verify the blade tension (should be printed on the blade package). Verify the guides are good and square. After that, you’ll get into “tier two” problems like worn tires and misaligned wheels. They’re less common, but they happen.

          • Rene Noble

            Alex Snodgrass bandsaw clinic. Google the YouTube video. Used his setup with all my shop bandsaws as well as my own, personal cheap Ryobi. Zero blade drift. Period. And it has nothing to do with the fence, co-planar wheels, high tension on the blade, or having every guide set up with zero clearance.

            The key to his setup is running the gullet of the blade on the crown of the top wheel. All clearances on the side guides, rear guides, top and bottom are 1/32″-1/16″ and the blade is run with 1/8″ deflection at the table from light finger pressure with the upper guide opened up to full capacity.

            I don’t re-saw anything larger then 12 inches at the shop, but I can cut you a 1/32″ veneer with about 30 seconds to measure and clamp my fence. As long as the table is square and plumb with the blade, I can even use an engineer’s square on 4′ or less stock to make a cut with no drift.

            I’m not some sort of shill for the man, but his method has rendered all the fancy jigs and calibration blocks in our shop to a bin in the back room. My personal Kreg bandsaw fence is lost somewhere in the garage.

            The only drawback I see to running the blade gullet on the crown of the top wheel is when we cut metals, quite a bit of it will get embedded into the tire, requiring a thorough brushing, but those machines do nothing but metal anyway, so I can deal with more frequent tire replacement in lieu of improved setup time any day