Product Summary

Longze High-Precision Parallel Keys (DIN 6885 Form A) are critical components used to transmit torque between shafts and rotating machine elements like gears, pulleys, or

couplings. Manufactured in Yongnian, China, our shaft keys are produced from cold-drawn key steel with a controlled tensile strength of over 600 MPa. Whether for precision

electric motors, agricultural machinery, or heavy-duty industrial gearboxes, Longze parallel keys provide the exact fit and shear resistance required for high-torque mechanical drive systems.

• ✔ h9 Precision Tolerance: Our cold-drawn process ensures a strict h9 tolerance on width and height, guaranteeing a reliable "push-fit" into standard ISO keyways without excessive filing or loose play.

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• ✔ Rounded Ends (Form A): Precision-milled rounded ends ensure stress is distributed evenly within the keyway, preventing localized fatigue cracks in the shaft.

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• ✔ High Shear Strength: Utilizing C45+C or Stainless 316 steel, our keys are engineered to act as a reliable mechanical fuse—strong enough to transmit power, yet designed to protect the shaft under extreme overload.

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• Standards: DIN 6885A (Form A), ISO 773, BS 4235.

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• Width Range: 2 mm to 100 mm.

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• Length Range: 6 mm to 500 mm (Custom lengths available for long-shaft applications).

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• Shape: Square and Rectangular cross-sections.

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• Material: Carbon Steel (C45 / S45C) | Stainless Steel 304 (A2) & 316 (A4).

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• Surface Finish: Plain/Oiled (Standard), Zinc Plated, Stainless Polished.

Mechanical Properties & Material Standards

• Matching the steel grade to the structural requirements of the transmission line.

• Material Grade	Tensile Strength (Rm)	Yield Strength (Re)	Hardness (min)	Best Application
  C45+C (Steel)	≥ 600 MPa	≥ 450 MPa	160 - 210 HB	General Gearboxes / Motors
  SS304 (A2)	600 - 750 MPa	350 MPa	180 - 240 HV	Food Processing Machinery
  SS316 (A4)	700 - 850 MPa	450 MPa	200 - 280 HV	Marine / Chemical Pumps

Standard Cross Arm Dimensions

• Common angle steel configurations for standard utility pole mounting.

• Width (b) x Height (h)	Shaft Dia (d) Range	Keyway Depth (t1)	Tolerance (Width)	Weight (kg/1000mm)
  8 x 7 mm	22 - 30 mm	4.0 mm	h9 (-0.036 mm)	0.44 kg/m
  10 x 8 mm	30 - 38 mm	5.0 mm	h9 (-0.036 mm)	0.63 kg/m
  12 x 8 mm	38 - 44 mm	5.0 mm	h9 (-0.043 mm)	0.75 kg/m
  16 x 10 mm	50 - 58 mm	6.0 mm	h9 (-0.043 mm)	1.26 kg/m

Galvanizing & Corrosion Resistance

• Ensuring 30+ years of service life in corrosive environments.

• Surface Treatment	Process	Salt Spray Test	Service Life	애플리케이션
  Plain (Oiled)	Cold Drawn	< 12 Hours	Moderate	Oil-Immersed Gearboxes
  Zinc Plated	Electrolytic	24 - 48 Hours	High	Dry Mechanical Drives
  Stainless 316	N/A	1000+ Hours	Extreme	Submersible Pumps

Avoid Pitfalls:

• Oversized Tolerance: If the key is even 0.05mm too wide, it won't fit the shaft. Longze uses Digital Laser Micrometers to check width and height on every batch to ensure h9 compliance.

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• Poor Straightness: A warped key causes vibration. We implement a secondary straightening process for keys longer than 100mm to ensure perfect alignment along the shaft axis.

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• Incorrect Chamfering: Sharp edges can snag. Every Longze key features a precise 0.2 to 0.5mm chamfer on all long edges to facilitate smooth installation and prevent stress risers.

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Perfect Fit Assembly:

• Matching Keyway Depth: Ensure your shaft and hub keyways are cut to DIN 6885 standard depths (t1 and t2) to allow for the proper top clearance, preventing the key from bottoming out and cracking the hub.

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• SS316 for Pumps: In water treatment or chemical pumps, we strictly recommend SS316 (A4) keys to prevent galvanic corrosion between the key and a stainless shaft.

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Quality Control & Logistics:

• ISO 9001 Certified: 5-step QC including hardness verification, h9 tolerance gauging, and 100% visual inspection for surface scores or tool marks.

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• Sea-Worthy Packaging: Keys are oiled and vacuum-sealed in plastic to prevent oxidation, then packed in reinforced inner boxes and palletized for export from our Yongnian hub.

• Q: Do you supply Form B (Square Ends)? A: Yes, while Form A (Rounded Ends) is standard, we also manufacture Form B (Square) for older machinery or specific custom hub designs.

• Q: Can you provide "Key Stock" in 1-meter lengths? A: Absolutely. We provide both finished cut-to-length keys and 1000mm long Key Steel bars for customers who prefer to cut their own onsite.