Thin-walled inserts and method of making same

Claim 1

AN INSERT, COMPRISING: A TUBULAR BODY HAVING A SERIES OF INTERNAL AND A SERIES OF EXTERNAL THREADS EXTENDING OVER SUBSTANTIALLY THE ENTIRE LENGTH OF SAID BODY, SAID EXTERNAL THREADS BEING ONE SIZE LARGER THAN SAID INTERNAL THREADS, THE EXTERNAL ONE OF SAID SERIES OF THREADS HAVING A ROOT DIAMETER SUBSTANTIALLY GREATER THAN NORMAL TO PROVIDE THREADS SUBSTANTIALLY LESS THAN STANDARD IN DEPTH, SO THAT 50 TO 55 PERCENT OF THE STANDARD DEPTH REMAINS, WHEREBY TO PROVIDE A THIN WALL BETWEEN SAID INTERNAL AND SAID EXTERNAL THREADS, SAID INSERT HAVING A PLURALITY OF DRIVE GROOVES FORMED IN ITS INTERIOR AND INTERSECTING AT LEAST THE FIRST TWO CONVOLUTIONS OF SAID INTERNAL THREADS, SAID EXTERNAL THREAD HAVING A PORTION OF ITS ROOT COVERING AT LEAST ONE THREAD CONVOLUTION DISPLACED INWARDLY WITH A CORRESPONDING REDUCTION IN DIAMETER OF THE PORTION OF THE INTERNAL THREAD ALIGNED THEREWITH TO PROVIDE AN INTERNAL LOCKING THREAD, EXTENDING OVER AT LEAST ONE THREAD CONVOLUTION, SAID BODY BEING COUNTERBORED AT AT LEAST ONE END IN THE REGION OF SAID EXTERNAL THREADS TO PROVIDE A THIN EXPANDABLE WALL PORTION FOR LOCKING THE INSERT AGAINST ROTATION IN A BORE IN A BODY, SAID EXTERNAL THREADS SURROUNDING SAID COUNTERBORE BEING SERRATED TO PROVIDE TEETH FOR PENETRATING THE WALL OF SAID BORE.