Quantum 10K II - Manual (Page 49)

Installation
3 − 22 Quantum Atlas 10K II Ultra 160/m SCSI Hard Disk Drives
The PCBA is very close to the mounting holes. Figure 3-11 specifies the clearance
between the screws in the mounting holes and the PCBA. Do not use mounting
screws longer than the maximum lengths specified in Figure 3-11. The specified
screw length allows full use of the mounting hold threads while avoiding damage or
stress on the PCBA. Clearance from the disk drive to any other surface (except
mounting surfaces) must be a minimum of 0.05 inches (1.25 mm).
Figure 3-11 Mounting Screw Clearance for the Quantum Atlas 10K II Ultra 160/m
SCSI Hard Disk Drive
Leave this mounting hole unused when
installing the drive with less than 4 bottom
mounting screws.