Analytical chainomatic balance No. 9

The special construction of the beam arrest not only insures the positive alignment  of the agate edges with their respective bearings, but is so designed that the center agate knife edge is directly over the center of the column. This is of great importance when the balance is loaded to full capacity and where the greatest precision is required. The beam arrest arms and the beam being pivoted about a common axis, the supporting points of the arrest arms move through the same arc as the supporting points of the beam, so that contact between edge and bearing always remains the same, thus the acme of balance construction is reached, the shifting of the beam with the consequent dulling of the agate edges rubbing over their respective bearings being entirely precluded.