Name: KJH/KJL Mini Pneumatic Fittings | 4mm/6mm to M3/M5 Thread
Brand: Sun Cheong Computer Company Limited
SKU: 21PS001850
Price: 8.0 HKD
Availability: InStock

Short Product Description

Build and repair micro-pneumatic systems with ease using ourKJH (Straight) and KJL (Elbow) Mini Pneumatic Fittings. Designed for tight spaces, these push-to-connect (PTC) adapters allow for instant, tool-free connection of 4mm and 6mm PU/Nylon tubing to micro air cylinders and solenoid valves. Featuring precisionM3 and M5 metric threadswith built-in O-ring seals, they guarantee a 100% airtight fit without messy Teflon tape. Need help identifying your thread size?Sun Cheong Computer Co. Ltd.has over 20 years of automation expertise. Visit our Sham Shui Po physical store for instant pickup and on-site thread matching!

Key Features

Ultra-Compact Design: Miniature footprint specifically designed for micro-cylinders, small solenoid valves, and tight robotic enclosures.
Instant PTC Connection: Tool-free push-to-connect design securely grips 4mm and 6mm PU or Nylon air tubing.
Straight & Elbow Options: Choose the KJH series for straight inline connections, or the KJL series for 90-degree routing.
360-Degree Swivel (KJL Models): The L-shaped elbow bodies can rotate freely after installation for optimal cable management.
O-Ring Seal: Precision M3 and M5 metric threads feature a built-in gasket, eliminating the need for messy thread sealants.
Corrosion Resistant: Constructed from durable nickel-plated brass and high-strength plastic for long-lasting industrial use.

Full Product Description

Micro-Pneumatic Connectivity Made Simple

When working with miniature air cylinders, robotic grippers, or compact solenoid valves, standard pneumatic fittings are often too bulky. The KJH and KJL Series Mini Pneumatic Fittings are engineered specifically for micro-automation. Their ultra-compact footprint allows you to route air lines in incredibly tight spaces, making them the go-to choice for precision robotics, 3D printers, and automated assembly machines.

Instant Push-to-Connect Efficiency

Save time on your assembly line or DIY project. These fittings utilize advanced Push-to-Connect (PTC) technology. Simply push your 4mm or 6mm polyurethane (PU) or nylon tubing into the white release ring, and the internal stainless steel claws will instantly lock it into place. To remove the tube, just depress the ring and pull. The KJL Elbow models also feature a 360-degree swivel body, allowing you to route your hoses perfectly even after the fitting is tightened.

Built-in O-Ring for Leak-Proof Sealing

Unlike larger PT or NPT pipe threads that require thread sealant or Teflon tape, these micro fittings use M3 (M3x0.5) and M5 (M5x0.8) metric threads. Each fitting comes equipped with a premium rubber O-ring at the base of the thread. When tightened against a flat port surface, this O-ring compresses to create a flawless, airtight seal, preventing pressure drops in your pneumatic circuit.

💡 Pro Tip from Our Technicians

"A common mistake we see is users trying to wrap Teflon tape around these tiny M3 and M5 threads—don't do it! The built-in O-ring is all you need for a perfect seal. Wrapping tape can actually prevent the O-ring from seating properly and cause leaks. If you are repairing a machine and aren't sure if your port is M3, M5, or 1/8", bring the part down to our Sham Shui Po store! Our team at Sun Cheong Computer Co. Ltd. will use our thread gauges to find you the exact match on the spot."

Technical Specifications

Specification	Details
Available Models	KJH04-M3, KJH04-M5, KJL04-M3, KJL04-M5, KJH06-M5
Fitting Types	KJH (Straight / Inline) KJL (90° Elbow / L-Shape)
Applicable Tube OD	4mm / 6mm
Thread Sizes	M3 (M3 x 0.5 metric) M5 (M5 x 0.8 metric)
Fluid Type	Compressed Air (Pneumatic Only)
Seal Type	Built-in NBR O-Ring
Applicable Tubing Material	Polyurethane (PU) / Nylon
Body Material	Nickel-Plated Brass & High-Strength Plastic

Delivery Options

Local delivery within Hong Kong and in-store pickup.
Free shipping for orders of HK$400 or above; HK$35 shipping fee for orders below HK$400.
Shipped by SF Express, usually dispatched the same day for orders confirmed before 6:00 PM (Mon–Sat).
Estimated delivery time: 1–3 business days after dispatch (Hong Kong).
In-store pickup details (location and time) will be confirmed by email or phone message.
Delivery times are estimates and may be affected by weather or unforeseen circumstances.

FAQ Section

What is the difference between the KJH and KJL models?The KJH models are straight fittings, meaning the air tube connects in a straight line with the threaded port. The KJL models are 90-degree elbow fittings, which are ideal for routing air tubes sideways in tight spaces. The KJL elbows can also swivel 360 degrees after being screwed in.
Do I need to use Teflon tape on the M3 and M5 threads?No. Unlike larger tapered pipe threads (like 1/8" or 1/4" PT), M3 and M5 are straight metric threads. These fittings come with a built-in rubber O-ring at the base. Simply tighten the fitting until the O-ring compresses against the port surface for a perfect, airtight seal.
How do I safely remove the air tube from the fitting?First, ensure the pneumatic system is completely depressurized. Then, push the white plastic release ring inward (towards the metal body) and hold it down while pulling the tube out. Never forcefully yank the tube without pressing the ring, as this will damage the internal locking claws.

Target Users / Applications

Robotics Engineers: Routing air lines to micro-pneumatic grippers and actuators on compact robotic arms.
3D Printer Modders: Upgrading air-assist nozzles or custom pneumatic tool changers on CNC machines.
Factory Automation Maintenance: Replacing broken M3/M5 fittings on miniature solenoid valve manifolds.
Animatronics Builders: Connecting 4mm air lines to tiny cylinders hidden inside stage props and models.