Thread casting method

Claim 1

IN THE ART OF PRODUCING A CAST CYLINDRICAL ARTICLE HAVING AN EXTERIORLY THREADED END PORTION AND HAVING THE THREADS REINFORCED BY LENGTHS OF FIBROUS MATERIAL EXTENDING CIRCUMFERENTIALLY OF THE ARTICLE WITH A LONGITUDINAL PITCH SIMILAR TO THAT OF THE THREADS, THE METHOD OF FORMING AN ORIENTING THE FIBROUSD THREAD REINFORCEMENT COMPRISING THE STEPS OF: WINDING LENGTHS OF REINFORCING FIBERS ABOUT A THIN-WALLED TUBULAR MANDREL, POSITIONING THE MANDREL COAXIALLY WITH AN END OF A CYLINDRICAL MOLD, THE MOLD BEING INTERIORLY THREADED AT THAT END AND HAVING A SMALLEST DIAMETER ONLY SLIGHTLY GREATER THAN THE EXTERIOR DIAMETER OF THE MANDREL, ROTATABLY INSERTING THE MANDREL INTO THE MOUTH OF THE MOLD WITH AN ADVANCE PER REVOLUTION APPROXIMATING THE PITCH OF THE MOLD THREADS, WHEREBY THE LENGTHS OF FIBROUS REINFORCEMENT MATERIAL WILL TRAVEL INTO THE MOLD ALONG THE VALLEYS OF THE MOLD THREADS, AND WITHDRAWING SAID MANDREL WHILE PREVENGING A COUNTER-ROTATION THEREOF TO LEAVE THE LENGTHS OF FIBROUS REINFORCEMENT LAID UP IN THE VALLEYS OF THE MOLD THREADS, AND INTRODUCING A SETTABLE MATERIAL INTO THE MOLD TO CAST THE TUBULAR ARTICLE.