Blade aligment question (front-to-back)

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  • craigjones

    #1

    Blade aligment question (front-to-back)

    I've used a BT3100 for a couple of years, off and on. It now appears that the blade is out of alignment. I'm talking front-to-back alignment, NOT vertical. With the rip fence on the right side of the blade, the front edge of the blade is further from the fence than the back edge by at least 1/16". This causes binding and burning on rip cuts.

    I see several posts about adjusting the rip fence for alignment, but it appears in my case that the rip fence is square to the table but the blade is not.

    Is there any way to align the blade with the fence, instead of vice-versa?

    Thanks for all suggestions.
  • JR
    The Full Monte
    • Feb 2004
    • 5636
    • Eugene, OR
    • BT3000

    #2
    Originally posted by craigjones
    Is there any way to align the blade with the fence, instead of vice-versa?
    Nope. The blade is fixed in that axis. Everything on the saw must be aligned in relation to the blade.

    I'm not sure what you meant by "rip fence is square to the table", but it's not really relevant. As you pointed out, if the fence is way out of whack, it needs adjusting.

    JR
    JR

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    • craigjones

      #3
      Thanks . . .

      I've taken off a few covers to get a look at the way the saw is mounted, but I haven't seen anything that looked partcularly adjustable re: front-back alignment.

      The rip fence is perpendicular to the rails, but the blade is not, is that clearer?

      If the saw is not perp to the rails, it seems wierd that the only correction is to make the rip fence AND SLIDING TABLE crooked to match the blade.

      Comment

      • LarryG
        The Full Monte
        • May 2004
        • 6693
        • Off The Back
        • Powermatic PM2000, BT3100-1

        #4
        Welcome to the forum, +1 on JR's comments; and yes, as weird as it sounds, that's the way the BT3x00 saws are designed. The rip fence and SMT (and the optional miter slot table, if you have one) are all aligned to the blade. If these items are then sitting cattywampus to the rails and/or table, it doesn't matter -- within reason, of course.

        Also:

        Are you checking the blade-to-fence distance using the same tooth? That is, take the front measurement, rotate the blade to the rear, take the rear measurement? This eliminates the blade runout variable (although 1/16" of runout would be awfully severe).

        Have you had the blade off? A chunk of debris between the arbor washers and the blade could be throwing things out of whack.
        Last edited by LarryG; 01-16-2008, 02:26 PM. Reason: tiepograffigal air
        Larry

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        • LCHIEN
          Super Moderator
          • Dec 2002
          • 21987
          • Katy, TX, USA.
          • BT3000 vintage 1999

          #5
          +2 on what's been said before. One of the compromises that makes the BT3 an affordable saw system is that the expensive motor mount adjustments have been foregone and you adjust the rip fence and SMT to the blade. The blade is king in this case. minor misalignments with the table are of no real consequence except perhaps it annoys those who think it should be.

          The rails are square to the table BUT not square to the SMT and rip fence, necessarily. However, the laws of geometry say that as long as the SMT and rip fence ride the rails at that angle, they'll stay parallel to the blade at any position.

          Trust us, it works.
          Last edited by LCHIEN; 01-16-2008, 03:25 PM.
          Loring in Katy, TX USA
          If your only tool is a hammer, you tend to treat all problems as if they were nails.
          BT3 FAQ - https://www.sawdustzone.org/forum/di...sked-questions

          Comment

          • craigjones

            #6
            Thanks LarryG . . .

            (And thanks to JR)

            I'll pull the blade off tonight and check to make sure the arbor is clean.

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