A grub screw, also known as a set screw, is typically a small, headless screw that is threaded along its entire length.
It is inserted into a threaded hole and tightened against another part to prevent relative motion.
Since it does not have a conventional hexagonal or slotted head like other screws, it is embedded completely within the part.
In front view, the grub screw appears as a simple cylindrical form with an internal feature, often a socket or hexagonal drive, for tightening.
Let's analyze the options:
- Option (i): Shows a cylindrical body with a hexagonal recess visible from the top (front view), and an internal dashed line representing internal threading. This is the correct depiction of a grub screw.
- Option (ii): Shows a head like a countersunk screw — this is not a grub screw.
- Option (iii): Depicts a flange, which is again inconsistent with a grub screw.
- Option (iv): Depicts a headed screw with visible contours, not matching the set screw's typical structure.
Hence, Option (i) accurately represents the front view of a vertical grub screw.
