Abstract: The roll comprises a solid, cylindrical, heat-treated steel rod having a threaded stud section on one end, and an externally knurled operating section on its opposite end. The stud section is adapted to thread into a bore formed in one end of the drive or work-rotating shaft of conventional roll grooving apparatus, thereby to support the operating section in the path of a conventional grooving roll which is mounted to reciprocate radially of the drive shaft between operative and inoperative positions. A circumferential groove in the operating section of the backup roll registers with a circumferential boss on the grooving roll. When one end of a piece of thin walled pipe is inserted over the operating section and the grooving roll is advanced against the pipe, the shaft is rotated and rotates the pipe so that the grooving roll forms a groove therein.