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Precision Stainless Steel Adjustable Shaft Couplers Threaded Extension Rods with Knurled Grip Sections
Custom
We are a leading precision turned parts manufacturer, specializing in high-quality and durable components. Our products are manufactured to the highest industry standards using state-of-the-art technology and years of experience.
minimum order
1 piece
Quantity
$1.00 - $1.00 / piece
We are a leading precision turned parts manufacturer, specializing in high-quality and durable components. Our products are manufactured to the highest industry standards using state-of-the-art technology and years of experience.
| Key Attributes | |
| Machining Capabilities | CNC Machining Processes:Broaching, Drilling, Etching/Chemical Machining, Laser Machining, Milling, Turning, Wire EDM, Rapid Prototyping |
| Materials Supported | Aluminum, Brass, Bronze, Copper, Hardened Metals, Stainless Steel, Steel Alloys, Plastic |
| Micro-Machining or Not | Micro Machining |
| Key Processes | CNC Milling, Turning, Drilling |
| Tolerance Standards | Industry-standard precision |
| Surface Treatments | Anodizing, Plasting, Polishing, etc. |
| Applications | Control Systems, Automotive Components |
| Place of Origin | Guangdong, China |
| Model Number | CUSTOM |
| Service Type | Customized OEM/ODM Manufacturing |
| Drawing Formats | PDF, CAD, IGES, STEP |
| Delivery Time | 7-30 Days |
| MOQ | 10 pcs |
· Product Overview
Introducing the YITECH Precision Stainless Steel Adjustable Shaft Couplers (Threaded Extension Rods with Knurled Grip Sections) — a pair of high-precision, modular mechanical components designed for fine-tuned length adjustment, rigid coupling, and secure axial connection between rotating or linear elements in robotics, automation, and precision instrumentation systems.
Each rod features a fully threaded shaft (M4/M5/M6) on one end, a central knurled grip section for manual rotation and torque transmission, and a smooth cylindrical head on the opposite end — enabling seamless integration into housings, bearings, or quick-release mechanisms. The two rods are shown crossed to highlight their symmetrical design and interoperability: they can be screwed together directly (via internal/external threads) or used independently as extension spacers, motor shaft adapters, or sensor alignment rods.
Crafted from A2-70 / 304 stainless steel, these couplers combine exceptional strength, corrosion resistance, and dimensional stability. The uniform matte brushed finish, precision-machined knurling, and tight thread tolerances ensure smooth operation, zero slippage, and long-term reliability — even under repeated cycling, vibration, or humid conditions.
Ideal for engineers who demand repeatability, adjustability, and tool-free handling without compromising rigidity.
· Core Specifications
| Feature | Specification |
|---|---|
| Material | AISI 304 Stainless Steel (A2-70 grade), fully annealed for optimal machinability |
| Surface Finish | Uniform matte brushed (Ra ≈ 0.3–0.5 μm); knurled sections diamond-rolled for high-grip texture |
| Overall Length | Standard: 45mm total (adjustable range: 30–60mm via threading); customizable up to 150mm |
| Shaft Diameter | Ø6mm (standard); optional: Ø4mm, Ø8mm |
| Thread Type | Metric external thread: M4 / M5 / M6 (fine pitch, Class 6g tolerance) |
| Knurled Section | Length = 12mm; pitch = 0.8mm; depth = 0.25mm — optimized for finger grip & torque transfer |
| Head End | Smooth cylindrical cap (Ø8mm × 4mm), chamfered for easy insertion into bearings or bushings |
| Tolerance | ±0.01mm (thread major diameter), ±0.02mm (length), concentricity ≤0.015mm |
| Processing Method | 5-axis CNC turning + knurling (diamond roller) + thread rolling + deburring + passivation |
| Max Axial Load | 1,000 N (static, M6 version); tested at 600 N dynamic (10G vibration, 500k cycles) |
| Torque Capacity | 3.5 N·m (M6, knurled grip) — sufficient for manual adjustment without tools |
| Operating Temp. | -40°C to +150°C (short-term up to 200°C) |
· Application Scenarios
These threaded adjustable shaft couplers excel in applications requiring precise, reversible length control and rigid mechanical linkage:
- Robotics & Actuation Systems
→ Adjustable linkages for robotic arms (e.g., elbow/wrist joint spacing)
→ Servo horn extensions with fine-tuning capability
→ Linear stage spacers for Z-axis height calibration - Sensor & Optics Integration
→ Laser module or camera focus adjusters on optical benches
→ Distance calibration rods for LiDAR/ToF sensors
→ Micro-positioning stages in lab equipment - CNC & 3D Printing
→ Belt tensioner rods with manual adjustment
→ Extruder drive shaft extenders
→ Tool holder height adapters - Industrial Automation
→ Pneumatic cylinder rod extensions with locking capability
→ Modular fixture spacers for jig reconfiguration
→ Conveyor idler shaft adjusters - DIY & Prototyping
→ STEM/robotics kits requiring variable-length joints
→ Drone payload alignment rods
→ Custom enclosures with user-adjustable component spacing
💡 Key Advantages:
- Tool-free adjustment: Knurled grip allows precise manual tuning (no wrench needed)
- Modular pairing: Two rods screw together to form a continuous, adjustable shaft
- Zero backlash: Cold-rolled threads + tight tolerances ensure repeatable positioning (<0.02mm error)
- Corrosion-proof: 304 stainless resists rust in workshop, outdoor, or humid environments
· Production Process Introduction
· Packaging and Shipping Methods
- Inner Packaging: 2 pcs (1 pair) per resealable anti-tarnish PE bag.
- Bulk Packaging: 100–2,000 pairs per cardboard box with custom foam dividers (prevents scratching).
- Shipping Options:
- 📦 Express (DHL/FedEx/UPS): 3–7 business days
- ✈️ Air Freight: 5–10 days (orders >1,000 pairs)
- 🚢 Sea Freight: 20–35 days (cost-effective for container loads)
- White-Label Service: Custom laser engraving (logo/part number), branded inserts, or kitted solutions (e.g., “Adjustment Rod Kit” with M5 screws + O-rings) available.
· Frequently Asked Questions (FAQ)
Q1: What is the MOQ?
A:
A:
- Standard size (Ø6mm, M5 thread, 45mm length): 200 pairs
- Custom thread (M4/M6), diameter (Ø4/Ø8), or length (30–150mm): 500 pairs
- Samples: 2–5 pairs free for verified B2B customers (shipping paid)
Q2: How long is the lead time?
A:
A:
- In-stock designs: 3–5 working days after payment
- Custom CAD (new geometry): 7–10 working days (includes design review & tooling)
- Rush service (≤4 days): Available for +20% fee (subject to capacity)
Q3: Can I customize the knurl pattern, thread pitch, or add features (e.g., set screw hole)?
A: Yes! Full customization supported:
A: Yes! Full customization supported:
- Knurl type: Straight, diamond, or custom pitch/depth
- Threads: M3, M4, M5, M6 (metric), UNC #4–#10, or metric coarse
- Length: 20mm – 150mm (adjustable range scalable)
- Features: Radial set screw hole (for locking), O-ring groove, flanged head, or hex drive recess
- Material: 316L stainless (marine), 6061-T6 aluminum (lightweight), or titanium Grade 2 (high-performance)
Just send a sketch, STEP file, or dimension list — we’ll reply with a quote and 3D model in <2 hours.
Q4: How do I use them together?
A:
A:
- Screw the threaded end of Rod A into the threaded end of Rod B (they are male-male — use a third female adapter if direct coupling isn’t desired).
- Rotate the knurled section to adjust total length precisely.
- For fixed position: tighten with a small hex key (2mm) on the head cap (if modified with hex recess) or apply thread locker (optional).
(Video demo and assembly guide available on our website)
Q5: Are CAD files provided?
A: Absolutely. Free downloadable:
A: Absolutely. Free downloadable:
- STEP / IGES / STL models (all standard variants)
- DXF templates for mounting plates
- Torque recommendations & installation guides
- Compatibility charts for common platforms (OpenBuilds, URM, Robotis, etc.)
· Why Choose YITECH?
✅ Engineered for Precision Adjustment — Not generic rods; designed for repeatable, tool-free fine-tuning
✅ Dual-Function Design — Knurled grip + smooth head = versatility in mounting and handling
✅ Industrial Durability — Cold-rolled threads + 304 stainless = 10x lifespan vs. stamped alternatives
✅ Fast & Flexible — Low MOQ, rapid prototyping, OEM kitting
✅ Trusted by Engineers Worldwide — Used in commercial robots, university labs, and aerospace prototyping
✅ Dual-Function Design — Knurled grip + smooth head = versatility in mounting and handling
✅ Industrial Durability — Cold-rolled threads + 304 stainless = 10x lifespan vs. stamped alternatives
✅ Fast & Flexible — Low MOQ, rapid prototyping, OEM kitting
✅ Trusted by Engineers Worldwide — Used in commercial robots, university labs, and aerospace prototyping
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