In the fabrication of structural steel members, such as wide flanged beams, channels and the like, the beams are conveyed through an automatic drilling machine where holes are drilled in the web and flanges of the beam in precise locations. In a conventional drilling machine, the beam is supported on a series of parallel lower rollers with the web of the beam being horizontal and the flanges extending vertically and one of the vertical flanges is positioned along a datum line at the side of the drilling machine. With large size beam, the beam will extend substantially across the drilling machine, while with smaller sized beams, the beam may extend only a fraction of the distance across the machine. In addition, the automatic drilling machine includes a group of upper rollers that are moved downwardly into clamping engagement with the upper edges of the vertical flanges of the beam.
When drilling small size beams, the upper rollers, when brought into clamping engagement with the upper edges of the beam, may tend to tilt or cant due to the fact that the smaller size beam extends only a fraction of the length of the clamping roller. The canting of the upper clamping roller can cause unequal pressure being applied to the beam and can result in improper alignment of the beam in the drilling machine.