Authoritative Answers, Fun, & Aloha -- no cost, no passwords, no popups
(as an eBay Partner & Amazon Affiliate we earn from qualifying purchases)

Home /
Site 🔍
pub     mobile?
Metal finishing Q&As since 1989


Q&A's about MIL-STD-171

Q. Is there a difference at all between MIL-STD-171F finish no. and from table II?

To me it looks like both default to same 1.2.2 which is AMSQQC320 class 2 chromium coating.

Steve Glover
- St. Catharines, Ontario
November 10, 2021

Q. Steve,
Yes, they are listed as the same thing. I suspect the separate listings are there for historical reasons, backwards compatibility to old drawings that list those finishes.

In fact, yes, if you look at the E revision, through were listed as Class 2a through Class 2e in QQ-C-320. Perhaps AMSQQC320 did away with the a through e subdivisions under class 2.

ray kremer
Ray Kremer
Stellar Solutions, Inc.
supporting advertiser
McHenry, Illinois
stellar solutions banner
November 12, 2021

November 15, 2021

thumbs up sign Thanks very much for chiming in Ray.

I obtained the old rev E of the spec from the Department of Defense website and I will look through it to see the differences.


Steve Glover [returning]
- St. Catharines, Ontario

⇩ Related postings, oldest first ⇩

Q. Hi, I have searched all over the web for what the specifications for Finish 5.1.1 of are and I cannot find them. Can anyone help me with this?


Joyce Hanni
- Manassas, Virginia

A. You searched all over the web? It took 15 seconds to type MIL-STD-171 5.1.1 into Google and find out that it is zinc phosphate.

jeffrey holmes
Jeffrey Holmes, CEF
Spartanburg, South Carolina

Q. Finding that the mil-std-171 includes zinc phosphate is little information to anyone searching for the ENTIRE standard and all of it's contents. Maybe you were able to find and download the entire standard?

Michael Dersch
- Rockaway, New Jersey

A. Hi, Joyce; Hi, Michael.

Most MIL specs are available for downloading at^

Just put "MIL-STD-171" into the 'Document ID' box.

The download is free (although there is nothing as expensive as "free") -- you are being taxed to fund someone (probably a beltway bandit who made substantial political contributions) to give your offshore competitors a free leg up on you. You are paying for all the "free" copies your Indian and Chinese competitors download; I guess you might as well get a "free" copy yourself :-)

Ted Mooney,
Ted Mooney, P.E.
Striving to live Aloha - Pine Beach, New Jersey

A. According to my hard copy of MIL-STD-171C dated 16 March 1979, finish no 5.1.1 is the general lead in to Metallic Coatings, usually applied by an electroplating or hot-dip process. The specific coating(s) are listed in Table II which is several pages long and includes a variety of metals and thicknesses of coating including Cadmium, Zinc, Gold, Aluminum, etc., each of which is covered by another referenced Military Specification.

Hope this helps.

Rich Johnson,P.E. (ret)
- Hopkins, Minnesota
March 28, 2009

A. Hi. Indeed it's a bit confusing because the document has a "section" 5.1.1 labeled "Detail Requirements, Metallic Coatings", but it also has a "finish" 5.1.1 which is, as Jeffrey described, Zinc phosphate:



Ted Mooney,
Ted Mooney, P.E.
Striving to live Aloha - Pine Beach, New Jersey
August 2013

Q. Need finishing spec MIL-STD-171 3.3.1, Heat treated 0-1 steel.

Tom O'Brien
machine & repair - Hamlet North Carolina
August 19, 2013

A. Hi Tom. MIL-STD-171 appears to have no section 3, and finish 3.3.1 appears to be "Black oxide for iron and steel, MIL-DTL-13924 [on DLA]".

But I'm not understanding whether you are looking for a copy of the spec (which this page tells you where to get), or whether you are saying that you are looking for a quotation on having the service done to your components. If the latter, please post something about size, volume, etc., so readers can determine whether they will be able to handle it. Thanks.


Ted Mooney,
Ted Mooney, P.E.
Striving to live Aloha - Pine Beach, New Jersey
August 2013

Q. My drawing states. Finish 4.1 of MIL-STD-171.

Can't figure out if it is paint or other coating.

John Moceri
- Sterling Heights, Michigan
February 13, 2020

A. Hi John. Personally I don't think it's either; I think it's just "Finish No. 4.1 -- Abrasive blasting (Method I of TT-C-490 [from DLA] )"

But it's always risky to ask a third party what the first party wants, and 'bad communication' still ranks as perhaps the biggest business problem, so I think you should require clarification before proceeding :-)


pic of Ted Mooney
Ted Mooney, P.E. RET
Striving to live Aloha - Pine Beach, New Jersey
February 2020

(No "dead threads" here! If this page isn't currently on the Hotline your Q, A, or Comment will restore it)

Q, A, or Comment on THIS thread -or- Start a NEW Thread

Disclaimer: It's not possible to fully diagnose a finishing problem or the hazards of an operation via these pages. All information presented is for general reference and does not represent a professional opinion nor the policy of an author's employer. The internet is largely anonymous & unvetted; some names may be fictitious and some recommendations might be harmful.

If you are seeking a product or service related to metal finishing, please check these Directories:

Chemicals &
& Software

About/Contact  -  Privacy Policy  -  ©1995-2024, Pine Beach, New Jersey, USA  -  about "affil links"