CL275-2 Steel (White Zinc Plated) / CL275-2B SUS304 (Grinding Polished) 90° Concealed Hinge

Full Technical Specifications

• Model Variants:
  • CL275-2: Steel material, white zinc plated finish (cost-effective indoor use)
  • CL275-2B: SUS304 stainless steel material, grinding polished finish (corrosion-resistant outdoor/hygienic use)
• Maximum Opening Angle: 90°
• Overall Dimensions: 67mm total length × 21mm side height
• Main Body Length: 60mm
• Pivot Pin Diameter: Φ5mm
• Mounting Holes: 2 pieces Φ5.4 through holes with Φ9.5×90° countersunk counterbores, 53mm center spacing
• Side Profile: 21mm total height, 17mm, 9mm internal, 2.5mm, 22.5mm bracket width, 17mm inner, >4.5mm clearance, t=3mm door panel
• Bracket Bend Angle: 90° (matching the 90° opening angle)
• Installation Type: Concealed U-channel design with countersunk flush mounting
• Core Features: Dual material options (steel/SUS304), concealed hidden design, 90° limited opening, countersunk flush mounting, Φ5 pivot pin, white zinc or polished finish

Core Product Features & Advantages

1 Dual Material Options for Flexible Application Matching

The hinge is available in two carefully engineered material variants to suit different environmental and budgetary requirements: CL275-2 manufactured from robust steel with white zinc plating, offering cost-effective corrosion protection for standard indoor industrial applications; and CL275-2B manufactured from premium SUS304 stainless steel with grinding polished finish, providing superior corrosion resistance, hygienic easy-to-clean surface and premium appearance for outdoor, coastal, medical and food processing applications.

2 90° Limited Opening Angle for Space-Constrained Applications

The 90-degree maximum opening angle is specifically designed for applications where door swing space is limited or where a full 180° opening is not required. The calibrated 90° stop prevents the door from striking adjacent equipment, walls or obstacles, making it ideal for compact enclosures, tight installation spaces and applications where controlled limited door swing is preferred.

3 Concealed U-Channel Design for Clean Exterior Appearance

The innovative U-channel concealed design ensures that minimal hinge hardware is visible on the exterior of the cabinet door when closed, creating a clean, seamless and professional appearance. The hinge body mounts within a recessed channel on the cabinet frame, while the extended Φ5 pivot pin engages with the door panel, providing a hidden hinge solution ideal for applications where aesthetic appearance is important.

4 Countersunk Flush Mounting for Snag-Free Exterior

The 2×Φ5.4 mounting holes are machined with Φ9.5×90° countersunk counterbores, allowing M5 flat head screws to sink completely flush with the mounting surface. This creates a smooth, snag-free exterior that eliminates protruding screw heads, improving safety, aesthetics and ease of cleaning. The flush mounting is particularly suitable for concealed applications where a clean appearance is desired.

5 Φ5 Precision Pivot Pin for Smooth Durable Rotation

The Φ5 precision-machined pivot pin ensures tight clearance, low-friction rotation and minimal wobble, delivering smooth and quiet operation over tens of thousands of open-close cycles. The solid steel or SUS304 pin provides reliable load-bearing capacity for medium-weight cabinet doors.

6 Compact 67mm Footprint with Robust Construction

With a compact 67mm overall length and robust U-channel construction (2.5mm wall thickness, 3mm door panel compatibility), this hinge provides structural rigidity and reliable performance while fitting neatly within standard cabinet configurations. The 90° bracket bend ensures proper door-frame clearance and smooth operation for limited-swing applications.

Application Fields

1. Compact electrical control boxes, small distribution cabinets and space-constrained PLC enclosures requiring limited door swing
2. CNC machine tool mini-access panels, automation equipment small protective doors and compact machinery access hatches
3. Communication equipment compact cabinets, small server modules and space-limited signal transfer enclosures
4. Outdoor monitoring equipment, weather-resistant compact instrument panels and coastal small enclosures (SUS304 CL275-2B recommended)
5. Medical devices, portable diagnostic equipment and laboratory compact instruments (SUS304 CL275-2B recommended for hygiene)
6. Food processing small equipment, stainless steel compact sanitary cabinets and hygienic mini-enclosures (SUS304 CL275-2B recommended)
7. Sheet metal small tool cabinets, compact industrial console doors and space-limited storage enclosures
8. Marine compact equipment, RV accessories, boat small fixtures and outdoor miniature devices (SUS304 CL275-2B recommended)
9. Aluminum profile compact industrial frames, small mechanical equipment maintenance hatches and mini test fixtures
10. Applications where 90° limited opening, concealed flush-mounted hardware and flexible material options are required

Installation & Maintenance Guidelines

Step-by-Step Installation Procedures

1. Select the appropriate material variant: CL275-2 (steel, white zinc) for indoor cost-effective use, or CL275-2B (SUS304, polished) for outdoor/corrosive/hygienic use
2. Determine the installation positions on both the cabinet frame and door panel according to the dimension drawing
3. On the cabinet frame: prepare a U-channel recess matching the hinge body dimensions (21mm height, 2.5mm wall thickness)
4. Mark and drill 2×Φ5.4 through holes at 53mm center spacing on the cabinet frame
5. Machine 90° countersunk counterbores to Φ9.5 diameter on the mounting surface side to accommodate M5 flat head screws
6. On the door panel (t=3mm): drill a Φ5 hole at the corresponding position to accommodate the pivot pin
7. Insert the hinge body into the U-channel recess and fasten with M5 flat head screws through the 2 countersunk holes
8. Confirm that all screw heads are completely flush with the mounting surface and do not protrude
9. Align the door panel with the Φ5 pivot pin and ensure proper engagement
10. Test the 90° opening movement for smooth rotation and verify that the door stops at the correct angle
11. Adjust the mounting position slightly if needed to achieve proper door alignment and consistent gap spacing

Installation Quantity Recommendation

• Door height ≤500mm: Install 2 concealed hinges symmetrically (top and bottom)
• Door height 500mm to 1000mm or medium-weight steel door: Install 3 hinges (top, middle, bottom) for balanced load distribution

Maintenance Instructions

1. CL275-2 (steel, white zinc): Suitable for indoor dry environments; not recommended for long-term outdoor exposure, high-humidity areas or coastal salt spray
2. CL275-2B (SUS304, polished): Suitable for both indoor and outdoor environments, including damp, coastal and mildly corrosive conditions
3. Wipe the surface periodically with a soft dry or slightly damp cloth to remove dust and grease; for SUS304 polished variant, use a microfiber cloth to maintain the polished finish and avoid abrasive cleaners
4. Apply a small amount of dry lubricant to the Φ5 pivot pin every six months to maintain smooth and quiet rotation
5. Check the 2 countersunk M5 mounting screw tightness quarterly to prevent loosening from vibration
6. CL275-2: Inspect the white zinc plating annually for chips or scratches; touch up with zinc-rich paint if necessary to maintain rust protection
7. CL275-2B: Inspect the polished surface annually for scratches or corrosion; for coastal applications, rinse with fresh water periodically to remove salt deposits
8. Inspect the pivot pin and barrel assembly annually for any signs of wear, binding or excessive play
9. Verify that the 90° opening stop remains functional and that the door does not exceed the intended opening angle
10. Verify that the U-channel mounting remains secure and that the door opens and closes smoothly without binding

Product Summary

CL275-2 is a concealed U-channel hinge with 90° limited opening, available in two material variants: CL275-2 manufactured from steel with white zinc plating for cost-effective indoor use, and CL275-2B manufactured from SUS304 stainless steel with grinding polished finish for corrosion-resistant outdoor and hygienic applications. Its 90° calibrated opening is ideal for space-constrained applications, the innovative concealed design provides a clean seamless exterior appearance, the Φ9.5×90° countersunk flush mounting with M5 flat head screws creates a snag-free surface, and the Φ5 precision pivot pin ensures smooth reliable operation. With its compact 67mm robust U-channel construction and flexible material options, it is an ideal hardware solution for compact electrical cabinets, machinery enclosures, communication equipment, medical devices, food processing enclosures, outdoor equipment and various industrial applications requiring hidden hardware with limited door swing and appropriate corrosion resistance.

CL275-2 steel SUS304 concealed hinge 90 degree white zinc plated grinding polished 2-Φ5.4 Φ9.5×90 countersunk holes Φ5 pin industrial cabinet equipment door hinge CL275-2B