Heim joint size chart: metric and inch specifications

Decoding the standard size chart

When you look at a technical spec sheet, the numbers can be overwhelming. Most charts, including those for the SYZ JMX series, follow a standardized naming convention that identifies the shank size and the hole size.

• Bore Size: The internal diameter of the ball where the mounting bolt passes through.
• Thread Size: The diameter and pitch of the threaded shank. Note that in "oversized" joints, the thread may be larger than the bore (e.g., a 5/8" bore with a 3/4" thread) to provide extra strength at the shank.
• Ball Width: The thickness of the spherical ball, which determines the bracket spacing you’ll need.

Standard sizing benchmarks

According to SAE J1120 and ISO 12240-4 standards, dimensions must be consistent to allow for interchangeability between brands.

1. Inch Series (UNF): Common sizes for steering are 5/8-18 and 3/4-16. For heavy 4-links, 7/8-14 and 1-1/4-12 are the industry standards.
2. Metric Series: Popular in European and Asian machinery, ranging from M6x1.0 for small linkages to M20x1.5 for heavy-duty suspension components.

Related Articles:

• How to Measure a Rod End Like a Pro (Bore, Thread, Shank).
• Metric vs. Inch: Which Sizing System Should You Choose?

Danny Ni Engineering & Mechanical Systems Writer

Danny Ni is an engineering-focused technical writer at SYZ Machine, specializing in mechanical components, linkage systems, and real-world application engineering. His work covers aftermarket vehicle parts, industrial joints, and mechanical principles, translating complex engineering concepts into practical insights for engineers, fabricators, and industry buyers.

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