Abstract: A lightguide preform chuck (15) comprises a collet (32) having a slotted conical end (36) and collet restraining means (40/42/45) in engagement with the collet ends but spaced from a collet mid-portion. The restraining means has a coefficient of thermal expansion less than that of the collet whereby under elevated temperature conditions the collet arches into gripping engagement with a lightguide preform held therein.

Abstract: Apparatus is provided for forming twisted conductor units which comprises a first power transmission train 12, 14, 16, 20, 21, 35, 40 having a rotatable member 40 coupled with a power source to which a bow 72, 75 is mounted for revolutionary movement in an orbit about a reel take-up space. The apparatus further includes means 65, 68 for supporting and rotating a reel about a reel axis within the reel take-up space and a second power transmission train 30, 31, 32, 33, 48, 50, 51, 54, 55 extending through the first power transmission train rotatable member 40 coupling the reel supporting and rotating means with a power source.