Small Indexing Plunger with Circle Plastic Clamping Knob, M8 x 1.0 x 15mm, D21, pin5
PSK300-2108150506
Spring loaded pull pin, Indexing plunger, Pop pin
Space-saving design ensures minimal interference in high-density hardware. If compact equipment needs indexing plungers with multiple aesthetics, UJEN offers M8–M16 mini plungers (4–10mm pins). The knob isn’t just ring-based but comes in four styles, plus 7 disc/ring color combos. Taiwan CNC and mold engineering deliver precise locking and durability, with optional wood fiber or oyster shell plastics to reduce waste. ISO9001-certified, we handle large volumes or custom orders across medical, sports, automotive-aerospace, and semiconductor B2B applications.
Function
UJEN Mini Spring Pull Pins are ideal for applications requiring compact size, frequent adjustment, and quick fastening. Simply pull the compact knob upward to release the pin from its hole, adjust the component to your desired position, and release—the internal spring immediately re-engages the pin for precise positioning.
Additionally, this pull pin features a special knob design allowing manual rotation to tighten screws directly by hand, ensuring stable clamping and preventing component vibration or loosening without needing tools. Perfectly suited for fitness equipment, medical devices, mechanical assemblies, and furniture hardware.
Features
- RoHS REACH compliant.
- Pull and release process smoother.
- Thread is class 2.
- Flame-proof, heat-resistant, anti-UV properties.
- The head knob has a matte finish.
- The head knob does not hurt hands, no sharp angles or burrs.
- The knob is easy to tight with a hand. the best design of beauty and grip.
- The metal is shiny and detailed.
- Zinc plated metal, stable corrosion resistance.
- The fitting tolerance between metal parts is small, reducing sway.
- The rounded corner of the Plunger's front end increases smoothness of insertion.
- The chamfered front end of the screw makes assembly smoother and reduces wear on the mating end face.
Dimensions

Thread Size
- M8 x 1.0
Thread Material
- Steel
Screw Length(mm/inch)
- 15 / 0.59
Plunger Diameter(mm)
- 5
Metal Finishing
- zinc plated with trivalent
External Diameter(mm)
- 21~24
External Height(mm)
- 21~24
External Material
- PA6+GF
External Shape
- Circle
Gallery
- Customized service for Bolt, Screw & Nut (metal parts)
- The center pin can be fitted with an anti-scratch pad to minimize scratches on the surface of the locked object.
- Optional accessories of knobs, handles, pull pins
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Details Add to List- FAQ
What measures does UJEN take regarding environmental protection?
Environmental protection is an integral part of our operation. UJEN is committed to reducing the environmental impact of our production processes, strictly...
In which fields are UJEN's handle screws applicable?
Our knob screws are widely used in various fields, including mechanical manufacturing, medical equipment, sports equipment, monitor stands, fitness equipment,...
How does UJEN handle customer feedback and after-sales issues?
Customer satisfaction is our top priority. We have a dedicated customer service team responsible for addressing customer feedback and after-sales issues,...
What makes UJEN's research and development in plastic head screws distinctive?
Our plastic head screw nuts R&D team consists of industry-experienced engineers and designers, possessing forward-thinking design concepts and deep technical...
What is UJEN's global market strategy?
As a company with an international outlook, UJEN actively expands into the global market, establishing stable cooperative relationships with clients in countries...
Small Indexing Plunger with Circle Plastic Clamping Knob, M8 x 1.0 x 15mm, D21, pin5 | Custom Hand Screws, Knobs & Handles Manufacturer | UJEN
UJEN's tool-free fastening solutions and custom adjustable handles are specifically designed for fitness equipment requiring frequent user adjustments. Our 45-year expertise in hand screw manufacturing ensures reliable, comfortable, and aesthetically pleasing products that enhance your equipment's market appeal. Contact us for customized solutions that streamline your production process.
UJEN's core strength lies in transforming customer concepts into market-ready products through innovative design-to-production services, technical consulting, and engineering solutions. Our tool-free fastening innovations and customization capabilities enable manufacturers to differentiate their products while reducing assembly time and improving end-user experience. Partner with UJEN to elevate your product competitiveness with premium hand screws and custom knob solutions backed by four decades of manufacturing excellence and commitment to quality craftsmanship.









