K72 4 jaw chuck

The K72 series is an independent 4-jaw chuck, meaning each jaw moves separately. When sourcing, you must prioritize the body material, typically high-grade cast iron (HT250) or forged steel for heavy-duty applications. Ensure the clamping accuracy is within 0.05mm to 0.10mm for standard industrial use. Additionally, verify the spindle interface type (e.g., A2, D, or threaded) to ensure it matches your lathe's mounting plate.

The jaws should be made of hardened steel (20Cr or 40Cr) with a surface hardness of HRC 50-60 to prevent premature wear. Ask the supplier for the heat treatment process used on the adjustment screws (lead screws) and the internal nut, as these components bear the most stress during manual tightening. Precision-ground jaw teeth are essential for maintaining a firm grip on irregular or rectangular workpieces.

For European markets, ensure the product carries the CE mark, indicating compliance with the Machinery Directive 2006/42/EC. For global quality assurance, the manufacturer should be ISO 9001:2015 certified. It is also critical to verify the maximum RPM (Rotations Per Minute) rating; exceeding the manufacturer's specified speed can lead to centrifugal force failure, posing a significant safety risk in the workshop.

The K72 is the primary choice for machining asymmetrical, rectangular, or irregular shapes that a self-centering chuck cannot hold. It is also preferred for high-precision eccentric turning and when the operator needs to eliminate run-out completely by manually adjusting each jaw. While the setup time is longer, it offers superior clamping force and versatility for custom engineering projects.

Request a pre-shipment inspection (PSI) or a video of the chuck running on a test bench. Look for signs of porosity in the cast iron body, which can lead to cracking under high pressure. For large orders, sourcing through reputable platforms like Made-in-China.com allows you to utilize Secured Trading services to ensure the product meets the agreed-upon technical benchmarks before final payment.

Focus on the net weight of the product; a lighter chuck often indicates inferior material density or hollowed-out sections. Negotiate based on Total Cost of Ownership (TCO), including the cost of replacement jaws and keys. For bulk orders (e.g., >50 units), aim for a 10-15% discount and request customized laser marking for your brand at no extra cost.

Due to the high weight-to-volume ratio, K72 chucks should be packed in fumigated wooden crates or reinforced double-wall cartons with foam inserts to prevent shifting. To avoid oxidation and rust during sea freight, ensure the supplier applies a thick layer of anti-rust oil and wraps the unit in VCI (Vapor Corrosion Inhibitor) plastic film.

Always use Incoterms 2020 (such as FOB or CIF) to clearly define the point of risk transfer. Ensure the HS Code (typically 8466.20) is correctly declared to avoid customs delays or incorrect tariff applications. When paying, prioritize Letter of Credit (L/C) or Escrow services provided by Made-in-China.com to protect your capital against non-delivery or sub-standard quality.