NAS 1149 Revision 1, “Washer, Flat,” has just been released and is available now from Document Center Inc. The National Aerospace Standard replaced the AN 960 back in 2011 (see our blog posting on the AN 960 cancellation). This is the first revision of the NAS document since it’s release.
The specification itself, along with NASM 15795 (previously MS 15795), is one of the most popular drawings on flat washers. It was originally formulated by the Army and Navy to standardize fasteners being used on military equipment.
Both documents were transferred to an industry association as a result of MIL Spec reform. This reflects both the desire of the military to get out of the spec writing business and the usefulness of both documents to industry in general.
The two specs call out the same material – a 300 series stainless with passivation. The differences are found in the manufacturing tolerances and dimension traits. The NASM 15795 has the largest outside and hole diameters. The NAS 1149 has a smaller outer diameter, and a tight tolerance on the inner diameter as well as the thickness.
Current and obsolete NAS, NASM, and MS documents are all available from Document Center Inc. at our web store, www.document-center.com. Or you may contact us by phone (650-591-7600), fax (650-591-7617) or email (info@document-center.com). We have worked with these documents since the 1980’s and can provide you with the expert service and support you need for your compliance collections.