Originally posted by gandalf
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The horizontal rod is fastened to the side of the level, then the 'T' assembly is fastened to it by means of the screw at the center of the plastic wheel. It has a brass tip, to not mess up the rod. By positioning the 'T' assembly on the rod as needed, and in the appropriate hole, cylinders from 3/8" or less, up to 3" as in the photo, or larger with bigger components, can be checked. That is a much wider range than a conventional sensitive level can handle. Note that the horizontal arm of the 'T' must be parallel to the vial. However this is easy to do. You can see, next to the screw holding together the two arms of the 'T', a small threaded hole, in which is a set screw pushing against the horizontal arm, with which the angle of the arm can be adjusted. To do so you place the level on top of the cylinder, center the bubble, then rotate it a little bit to one side, then to the other. If the position of the bubble changes as you do so, you adjust the angle of the horizontal arm with the set screw, until it does not. A moderate accuracy is sufficient for this, and it is easy to do.
This arrangement can be used for example to check for possible taper in a cylinder, especially if it is larger than your mikes will handle. By centering the bubble, then flipping the cylinder, the error will show up, double. So with some care very small errors will be seen, and can be measured with the level's micrometer.
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Our next attraction is a 90* square attachment to check vertical surfaces.


The level can be mounted on either arm of the square. One arm is wider, and shaped to get into small dovetails when needed. The supports for the level, and the outer faces, are scraped accurately to 90*. The supports are also pinpointed. To check a vertical surface the setup can be clamped, but at times that may be awkward, or impossible. So as an alternative, a small rare earth magnet, mounted in a steel cup, shown in the bottom photo, can be placed in the hole at the middle of the vertical arm, and can be adjusted with the thin knurled wheel. When not in use I store it in a plastic container, to keep it out of the way. [More in "Part 2," the next post].
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