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The National Association of Chain Manufacturers (NACM) is a non-profit business league headquartered in Tucson, Arizona. NACM has represented the domestic chain manufacturers of the USA since 1933, making it one of the oldest industry-specific non-profit trade associations in the nation. NACM was founded during the Great Depression at the instigation of the federal government, and was originally known as The Chain Institute. Business conditions of that era encouraged the formation of similar business leagues in an effort to simplify the variety of common products being made in the USA.

For the past fifty years, the principal activity of the association has been to devise model manufacturing specifications for various types of welded and weldless chain. NACM members thereby promote safety, utility, and more efficient application of the correct chain for the intended purpose. In 2002, in an effort to make the NACM copyrighted model specifications more readily available to the general public, the association began posting the specifications on its website. As of 2011, three sets of updated NACM specifications now can be downloaded by anyone free of charge simply by clicking a tab at the head of the home page.

The three sets of NACM specs carry the titles: Welded Chain, Weldless Chain, and Tire Chain. The association encourages the use of the various sizes, grades, and descriptions of chain meeting these specifications, but NACM does not inspect, approve, or certify products as complying with the requirements of these documents. The only restrictions applicable to anyone downloading the specifications are limits of the USA copyright laws which forbid reselling them.

Nine varieties of carbon steel, alloy steel, and stainless steel Welded Chain specifications, plus seven varieties of Weldless Chain specifications, and all of the most common North American Tire Chains are posted. NACM has a policy of updating its specification files every five years to keep them current.

The NACM specifications are posted in Adobe Portable Data File format (i.e. the dot-pdf extension) for easy and accurate printing, covering new products such as Stainless Steel Chain and Grade 100 Chain for lifting slings, as well as many traditional products such as Proof Coil Chain, Transport Chain and Plumbers Chain. The limits of NACM’s sector of interest are clearly defined. Chain-like merchandise, and items that look like chains such as jewelry chains, roller chains or bicycle chains, do not fall within NACM’s purview.

In addition to describing the physical characteristics of various kinds of chain, other important advisories have been developed by NACM for the benefit of the public. For example, members of the AWRF may be aware of terminology such as the commonly-used phrase “overhead lifting” which has been formally defined by NACM; the only organization to do so. Other NACM definitions have been posted on the website to assist the public.

NACM willingly cooperates with many other groups (in particular those involved with standards writing) and welcomes inquiries related to information found on its website.

For example, NACM currently is involved in an open dialog with the Defense Logistics Agency, Richmond VA as part of a line-by-line review of the federal procurement specification RR-C-271E “Chains and Attachments”. The most recent version of this federal specification, dated December 2010, is posted on the NACM website. Another good example of NACM cooperation with a federal agency is an on-going dialog with DOL-OSHA, maintained for the last 15 years leading to clarification of plain language Guidance on Safe Sling Use advisories.

NACM has worked in conjunction with the foremost publisher of national consensus standards – ASTM International. West Conshohocken PA – in establishing, revising, and harmonizing chain standards. NACM has provided input into revisions to reflect changes and improvements in chain manufacture and requirements. ASTM has published several chain standards including A906/A906M, the USA national standard for chain slings. For many years this was the only USA national consensus standard for any type of sling although efforts to achieve similar status for wire rope slings and synthetic slings are underway.

In addition to DLA, DOL-OSHA, and ASTM, several other well-known national and international organizations communicate periodically with NACM with regard to chain items, even though the chains involved may represent only a small part of their larger body of standards. This includes recognized standards-writing groups such as:

  • American Galvanizers Association (AGA)
  • ASME International (ASME B30)
  • Association of American Railroads (AAR)
  • Commercial Vehicle Safety Alliance (CVSA)
  • Entertainment Services & Technology Association
  • Federal Motor Carrier Safety Administration (FMCSA)
  • Society of Automotive Engineers (SAE)
  • Web Sling & Tie Down Association (WSTDA)

And several others. Likewise, a number of state regulatory bodies in those locations where the use of automotive chains for snow and/or mud travel as a matter of their motor vehicle laws also refer to NACM specifications. The Technical Committee of NACM meets at intervals to review and update the specifications, and to study other standards and chain-related issues.

Twenty years ago NACM launched cooperation with the information-gathering studies of the AWRF Technical Committee and its various testing programs. Several publications have appeared as the fruit of the joint effort. More recently, NACM began a dialog about chain slings with NCCER, publishers of the Contren Learning Series textbooks that are widely used by craft-training trade schools in the USA. Three years ago, NACM joined with the Pennsylvania Historical and Museum Commission and the Uniontown PA Public Library to erect a permanent roadside historical marker celebrating the bicentennial of James Finley’s 1808 chain bridge patent, the first American suspension bridge patent.




Phone: +1 520.886.0695

Fax: +1

Mail: P.O. Box 89014, Tucson, Arizona, USA, 85752-9014






  •  Reference ASTM A906/A906M-02 (2010) – Standard Specification for Grade 80 and Grade 100
  • Alloy Steel Chain Slings for Overhead Lifting and RRC-271D – Federal Specification: Chains
  • and Attachments, Welded and Weldless for rated load tables for chain slings.

Always refer to the manufacturers specifications/specified rated load tables.



  • NACM Welded Chain Specifications
  • NACM Weldless Chain Specifications
  • NACM Tire Chain Specifications  No. NACM 92805 (TC)
  • RR-C-271F – Federal Specification – Chains and Attachments, Carbon and Alloy Steel