112 (#166) ############################################ WOOLLEN AND WORSTED SPINNING the fibre moving its own length along the sliver then the rule for the draft will be fibre length 1 + fibre length This is true for any system of length measurement -British or metric, for example—but simply amounts to the statement that a spindle-draft of two should always be employed. And this is not true! For fibres under 1 in. much less draft is admissible, and the most suitable draft in all cases is approximated to by the rule- VL I + 2 = I.4 2 2 a 2 in which L = the length in inches of the longest fibre L in the blend. Example 1: With a 2-in. fibre the calculation stands V2 It = It = 1 + 7 = 1.7 spindle-draft required. 7 • Example 2 : With a I-in. fibre the calculation stands Vi I + = I + 5 = 1.5 spindle-draft required. Example 3 : With a t-in. fibre the calculation stands V•5 It = 1 + 35 = 1.35 spindle-draft required. - A similar empirical rule could no doubt be devised for the metric or any other system of length measure- ment of fibre. As there is usually no doubling in woollen spinning but only a levelling-up by reason of the twist distributing itself over the sliver during drafting approximately in proportion to the diameter of the sliver, it will usually not be safe to draft the slivers more than this : less may t t 1 2 II2