The Checkline STM-50 Tension Meter for Screen Printing is designed to measure how taut a woven material is when tension has been applied in two directions at right angles to each other, as in the case of a screen printing frame. Its operating principle is similar to that employed by the CHECK-LINE HP Yarn Package Durometers, except that if is fitted with a one-inch bar indentor placed midway between two outer "reference" bars spaced two inches apart, instead of an indentor ball. When the instrument is placed on the material, the greater the tension, the more the bar will be pushed in and the greater the reading on the scale.
