Quickscrews #9 x 3 inch flat head assembly screw square drive is a case hardened screw designed for assembly work where bite and drive control matter. The #9 gauge diameter and 3 inch length work together to pull parts together over a wider range of material thicknesses, so one size can cover more builds in the shop. The flat head profile lets the head sit flush in a countersunk hole, which keeps surfaces smooth and ready for later finishing or hardware overlay. The square drive recess is sized for #2 square drive bits, so bits grip the screw head positively and reduce cam-out during powered driving. The coarse thread pattern runs aggressively into material, helping the screw advance quickly and draw joints tight under consistent torque.
The #2 square drive interface on this Quickscrews assembly screw is engineered for a square drive bit, so the bit seats deeply in the recess and transmits torque directly. That engagement helps the screw track straight when starting, which is useful when placing fasteners close to edges or near other hardware. The coarse thread geometry on the #9 shank forms deep, spaced threads that bite into material fibers quickly, translating driver torque into forward motion instead of friction drag. Because 3 inch screws offer extended reach, having two-thirds of that length threaded from the bottom focuses the pulling force near the tip area, which helps parts clamp together firmly as the screw seats the flat head.
This Quickscrews #9 x 3 inch flat head assembly screw is part of the Quickscrews fasteners line described for assembly tasks, so it suits builds where components need to be pulled together over moderate distances using a single fastener size. The 3 inch length allows the screw to bridge thicker stackups while still driving the coarse thread portion deeply into the base material, which supports tight joints when parts are clamped or held in alignment. Because the flat head design sinks into a countersunk cavity, this screw is suited to locations where a flush surface is needed for panels, trim, or other hardware that bears against the work surface. The zinc finish ties visually with other zinc fasteners in the same project, which helps assemblies present a consistent, professional metal hardware look. By using the #9 diameter with a Type 17 auger style point, this screw provides an aggressive leading edge that engages material as soon as torque is applied, which supports use in repeated production-style assembly.
The square drive on this screw works with #2 square drive bits, giving installers a positive, four-sided interface that transmits torque without the wedging action of some other drive styles. This geometry helps bits stay centered in the recess, which supports straight driving and reduces wandering when starting screws at an angle relative to the work surface. The coarse thread pattern on the case hardened shank displaces material efficiently as it cuts its path, which means the screw progresses with fewer rotations and lets drivers run at working speed without excessive heat buildup at the interface. The Type 17 auger point at the tip is described as an auger style, so it begins cutting fibers as soon as the tip contacts the material, helping the screw ease into its path rather than abruptly forcing its way in. Because the length over 1 inch is threaded two-thirds from the bottom, the engaged threads concentrate their grip toward the tip while leaving a non-threaded upper section, which helps the screw draw the top piece tightly to the base material as the flat head seats into its countersink. Together, these features combine so installers using Quickscrews assembly screw square drive fasteners can run consistent depth and pull joints tight across repeated installations.
This Quickscrews #9 x 3 inch flat head assembly screw uses a square drive recess that matches #2 square drive bits, so installers can pair it with standard #2 square drive tooling.
This Quickscrews assembly screw follows the series rule that 1 inch lengths are fully threaded, while other lengths like this 3 inch size are threaded two-thirds from the bottom of the screw.
The Type 17 auger point on this Quickscrews assembly screw provides an auger-style cutting tip, so the screw starts into material by cutting fibers as torque is applied.
The Quickscrews 12621 assembly screw is case hardened, giving it a hardened outer surface that better resists wear at the head and threads during powered driving and backing out.
The coarse thread on this #9 Quickscrews assembly screw creates deep, widely spaced threads that advance quickly into material, helping joints pull tight with fewer driver rotations.
The Quickscrews 12621 flat head assembly screw has a zinc finish, so its surface presents a consistent zinc appearance that aligns with other zinc-coated fasteners in a project.
This Quickscrews #9 x 3 inch flat head assembly screw square drive combines a #2 square drive recess, coarse threads, and a Type 17 auger point, so it supports controlled driving and tight pull-up across assembly tasks. The case hardened construction and zinc finish align with production-focused environments, where repeated driving, removal, and visual consistency matter for ongoing jobs. For projects that call for a #9 diameter, 3 inch length, Type 17 auger point, and square drive interface, this 12621 Quickscrews assembly screw offers a configuration that matches those requirements at Wurth Baer Supply.
Sold In: 2000 Each