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(balance) scales
carrying pole; shoulder pole; milkmaid's yoke
thread take-up lever (on a sewing machine)
spreader bar
学生は粉末を天秤で量った。
The student weighed the powder on a balance scale.
彼はコストと品質を天秤にかけている。
He is weighing cost against quality.
天秤の針がゆっくりと動いた。
The needle of the balance scale moved slowly.