this invention relates to an improved apparatus and method capable of accurately measuring fixed lengths of moving strand or yarn as it is pulled from an essentially continuous source of supply and wound onto a take - up reel by an appropriately powered winding mechanism . in its preferred embodiment , the invention is used to measure lengths of fiber glass strand unwound from forming packages and onto rotating bobbins carried on a twist - frame . moving strand is maintained in continuous contact with a metering rim supported on an essentially frictionless layer of pressurized air thereby causing the rim to rotate . in particular , the improvement comprises means for bleeding off a portion of this pressurized air by allowing it to escape through the surface of the rim whereby any broken filaments which may break away from the strand are sloughed off from the surface of the rim before they tend to become wrapped about its circumference .