Non-detachable screw PF21-M3-12.3 long spring screw, non-falling screw

Non-Detaching Screw Nut
Applied to panel screws: Non-detaching screws, also known as spring screws. Non-detaching screws can be riveted onto iron plates, allowing free screwing in and out. The entire assembly remains securely embedded in the panel without detaching, hence also called non-falling screws. The outer hand-twist sleeve is typically embossed with straight knurls for easy hand-tightening or manual fastening, so it is also referred to as hand-tight screws or hand-twist screws.
Non-detaching panel screws (spring screws) can be used for installing PCB boards, occupying minimal space. The hand-tight screw's press-rivet sleeve features knurled teeth, pressed into the chassis or thin sheet holes (note: the drilled hole diameter of the thin sheet must meet specific requirements relative to the press-tooth diameter of the spring screw), forming an exposed spring screw that is hand-twisted at the other end (i.e., the hand-twist end). Due to the internal fixed spring, the screw moves in and out relative to the other end of the thin sheet. This solution addresses the challenge of frequently needing to remove screws and is very convenient and practical.

Name: Non-detaching screw, panel screw, spring hand-tight screw
Material: Combination of carbon steel screw, carbon steel press-rivet sleeve, and aluminum hand-twist sleeve; combination of stainless steel screw, stainless steel press-rivet sleeve, and aluminum hand-twist sleeve. The non-detaching panel screws produced by Yaoda Hardware*** are entirely manufactured and assembled in-house, except for the spring, which is outsourced, with strict quality control.
The panel spring screw (non-detaching screw) consists of several components:
1. Screw part (used to fasten the other end of the chassis thin sheet; typically made of carbon steel or stainless steel, with cross or slotted head for tool tightening)
2. Hand-twist sleeve (usually knurled with straight patterns, typically made of aluminum, sometimes anodized black as needed)
3. Press-rivet sleeve (used for riveting onto the panel)
4. Spring (facilitates the extension and retraction of the screw and prevents the entire assembly from detaching)
After each component is produced, they are assembled into one unit, and the hand-twist part is pressed to fit together with the press-rivet part via the spring, forming a complete non-detaching spring panel screw.