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  • Precision level question

    I aquired 2 Starrett levels,a 98-6 and a 98-12.I am a wet behind the ears total green horn home shop machinist and have no idea if I need either or both.If I need to have one which is the better choice? I do not see myself moving/setting machinery on a regular basis and I am pretty sure I don't need these for the odd carpentry job plus I have a couple of nice 4' carpenters levels.

  • #2
    The 98-6 is a good size to use leveling home shop machines . I have one and a 98-8 which is 8 inches long I use it the most . The 12 is probably more than you may need. This may help. It depends on what kind of machinery you may have but I suggest that you keep at least one.
    Every Mans Work Is A Portrait of Him Self
    http://sites.google.com/site/machinistsite/TWO-BUDDIES
    http://s178.photobucket.com/user/lan...?sort=3&page=1

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    • #3
      Do you know how to calibrate the level? That is more important than knowing how to use it.
      It's only ink and paper

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      • #4
        Calibration had crossed my mind but I have no idea how.

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        • #5
          Originally posted by BigMike782
          Calibration had crossed my mind but I have no idea how.
          I have a 98-12. You don’t need to send it anywhere to calibrate it. Simply find a level surface (or real close to level). Take a reading, then turn the level 180؛ and take another reading making sure the level is setting in the exact same place.

          If the bubble is not in the exactly same place, the level is out of calibration. I like to make a pointer with a sliver of masking tape and mark the locations of the bubbles. Then use the adjustment screw to move the bubble half the distance, until the bubble reads the exact place when spun 180؛.

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          • #6
            Originally posted by Carld
            Do you know how to calibrate the level? That is more important than knowing how to use it.
            How the hell is it important to have a calibrated level that you have no idea how to use?

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            • #7
              BigMike782, I would keep the 12" level. The 6" level may be a little small to check across the ways on larger machines, the 12" should work fine on larger machines and small ones too. I have a 98-8 which will cover everything I need to test... until it dosen't

              Tim

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              • #8
                Originally posted by BigMike782
                Calibration had crossed my mind but I have no idea how.
                As Ron of Va said, but be sure to let the level adjust the to the temperature of the room and machine your going to use it in/on for a couple hours first.
                Otherwise, as the level warms/cools to it's surroundings your calibration
                may change.
                I cut it twice, and it's still too short!
                Scott

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                • #9
                  If I needed to level across a span longer that the level is it a bad idea to use a straight piece of stable material to span the distance?
                  Last edited by BigMike782; 12-28-2011, 03:55 PM.

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                  • #10
                    Every piece you add to the 'measurement system' is going to introduce its own error. Over the years I've become aware of just how 'not straight' a straightedge usually is, or how unsquare a square is, etc.

                    Having both of those levels already- is there any reason to get rid of one or the other? I'd be keeping them both, and also looking for how the level vial is adjusted on each, then I'd be using a surface plate as a flat surface (level or not) on which to adjust and compare both levels.

                    One of the biggest parts of knowing how to use one of these is keeping the seating areas clean. The more sensitive the level, the more important this is.

                    When it comes to using the level, you already know the basics. What you have to know is what you're trying to accomplish- in the case of a lathe that is to get the front and rear ways not particularly perfectly level, but to the same degree of tilt. In other words parallel. They can be parallel without being level in the traditional sense. Level is good, but not mandatory.

                    You can lay the level across the ways, front to back, and that may not say 'level', but it should read the same whether you lay it across near the headstock or at the tailstock end. When you do this checking, you should be picking the same spot on the bottom of the level to sit against the ways at either end. That way, if the bottom of the level is not 'perfect', you will still be able to get an accurate comparison. You may have to set V blocks on the ways to set the level against, as it's the angled surfaces that you want to be referencing to. That's what supports the carriage after all. If the rear way is flat, then you use a V block on the front way, and a spacer on the flat way. The height of the spacer is determined once you have the V block firmly seated on the front way, and the level firmly placed against that. You definitely want your V block to orient to the way perfectly in order to give meaningful comparisons.

                    Of course, once you begin to adjust any twist out of the bed, you are going to learn all about the variations that happen when the bolts are tightened-
                    I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

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                    • #11
                      you could just put the level on the cross-slide.

                      Phil

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