The Qianli 4.0mm Drill Bit Heads 2.35mm (5pcs) give your grinding pen a larger cutting head for the heavy mechanical jobs that small polishing tips cannot finish. Each head carries a 4.0mm working diameter on a standard 2.35mm shank, so it drops straight into the collet of most rechargeable grinding and polishing pens used on Pakistani repair benches, including the Qianli SG-02, Qianli DM460-K, MaAnt D1, Mechanic IRX6, and Kaisi 328. You get five heads in one pack, which matters on a busy counter where one worn or chipped head slows every job after it. Think about the jobs that land on your bench every week: a bent frame corner that stops a new display or back glass from seating flat, a metal shield that refuses to lift because its edges have fused, a screw head that a previous technician stripped completely, or a rear housing lip that needs trimming before a replacement part fits. A fine needle tip takes forever on that kind of material, and a full-size rotary tool feels too clumsy near a motherboard. The 4.0mm head sits between those two extremes, removing material quickly while the pen body keeps your hand close to the work and steady under the microscope. When a phone comes in with a hardware fault hidden under a shield, you can cut the shield edge cleanly instead of pushing extra hot air into the area and risking nearby ICs. For stripped screws, you can grind a fresh slot or reduce the screw head enough to lift the bracket, then carry on with the actual repair, whether you are tracing a charging issue, a display problem, or a network issue on the board. Frame and housing work also moves faster, because the wider head shapes and levels metal or plastic edges in fewer passes, which saves real time on screen replacements where the new panel needs a flush seat. Speed control matters with any 4mm head. Start your pen on its lowest gear, let the head cut without pressing hard, and step up only when the material demands it. Heavy pressure builds heat, wears the head faster, and can slip the tip onto a flex cable or a nearby component. Keep a soft brush or air blower close to clear metal dust between passes, and always disconnect the battery before you grind anywhere near the board, because conductive debris on a live board can turn a simple fix into a dead phone. Work under your microscope for anything close to components, and use a PCB holder to lock the board or frame so it cannot spin with the head. Many shop owners in Lahore, Karachi, and Islamabad keep one pen loaded with a large head like this for mechanical work, while a second pen carries fine tips for chip polishing and pad cleaning. That split saves you from swapping heads twenty times a day and keeps your fine tips sharp for delicate board-level jobs. Because the shank follows the common 2.35mm standard, you also avoid buying brand-locked accessories every time you change your pen. The Qianli 4.0mm Drill Bit Heads 2.35mm (5pcs) fit neatly into a wider rework setup as well. Pair them with a hot air station for shield work, a soldering station for reattaching parts once you open the area, and a multimeter for checking lines after you reach the fault. If you still work without a dedicated grinding pen, a rechargeable model such as the Qianli DM460-K gives you a proper upgrade path that accepts these same heads. For technicians comparing grinding pen accessories price in Pakistan, a five-piece pack keeps your cost per job low and keeps a spare ready on the shelf. Add the pack to your regular consumables order and keep your bench ready for frame corrections, shield cutting, and stubborn screws without delaying the repair your customer is waiting for.
