Talk:Rockwell scale

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Inventor of Rockwell scale?[edit]

I seem to recall reading that the inventor of the scale was related to the famous American illustrator Norman Rockwell. Does anyone know if that is in fact true? The article makes no mention of the inventor at all. —Preceding unsigned comment added by (talk) 14:07, August 29, 2007 (UTC)

Stanley P. Rockwell[edit]

I took the liberty of adding a paragraph about the history of Rockwell hardness, and a bullet point regarding superficial Rockwell scales. Stanley P. Rockwell was the inventor, around 1919. His family was a big name in ball bearing manufacturing in and around Hartford, CT, at that time. The Rockwell bearing companies are now owned by the Swedish firm SKF, another big name in bearings. Stanley later started a heat treating company named after himself that still exists. I spoke to the plant manager of the Stanley P. Rockwell Co. by telephone in 2006, but he was not able to provide much historical information. I do not know whether Stanley was related to Norman. Author Vincent Lysaght was a longtime employee of the Wilson Mechanical Instrument Co. in New York City, and Charles Wilson wrote the foreword for his book.His Manliness (talk) 17:41, 21 February 2008 (UTC)

Hugh M. Rockwell (inventor) and Stanley P. Rockwell (metallurgist) developed the Rockwell Hardness tester while both were associated with The New Departure Manufacturing Co. in Bristol, Ct. Patent #1,294,171 was applied for on 7/15/1914, and issued on 2/11/1919. Hugh was the son of Albert F. Rockwell, the founder and President of New Departure (ball bearings, etc.) and has approximately 45 patents to his name. Hugh and Stanley were not directly related. After leaving New Departure, Stanley applied for a patent on an improved tester on 9/11/1919, and patent #1,516,207 was issued on 11/18/1924. Hugh became involved in aviation and munitions inventions and Stanley founded the Stanley P. Rockwell Co. in Hartford, CT. I understand that Hugh was distantly related to Norman Rockwell.--Eques3 (talk) 03:14, 8 August 2008 (UTC)

Typical values section[edit]

The example values in the article are subjective at best. There is no source citation they could've just been random numbers someone picked. (talk) 02:43, 5 May 2009 (UTC)

-Typical values are indeed correct. It is for materials engineers as sure as any citation can't be publisched about this. And citation of dubious source is good for nothing. -- (talk) 08:26, 4 August 2009 (UTC)

While most good American knives fall between 57 and 60, I have yet to read what that implies outside the world of metal. For example, 57 is approximately 60, suggesting not much actual difference. True? Also a benchmark in Moh's hardness is a file, what's that in Rockwell? And glass? Any brittleness limitations should be mentioned. And rubber? Remember the def given repeatedly is: "The Rockwell scale is a hardness scale based on the indentation hardness of a material." Is that too vague?
It also says: "by measuring the depth of penetration of an indenter under a large load compared to the penetration made by a preload." That seems counter-intuitive and should be explained. Preload dent...who cares, so what, why two dents?
-- (talk) 05:41, 3 July 2012 (UTC)Doug Bashford

It would be nice for those looking into this topic for the first time to have at least one clear statement along the lines of "Higher/lower numbers mean harder/softer materials." (talk) 19:24, 21 November 2012 (UTC)

Picture of the balls is not Rockwell.. If the rockwell test is the one with the cone, the 5mm ball is another type of hardness testing called brinell[edit]

You have a wrong picture in there... got a picture for brinell mixed in with rockwell (uses a cone) brinell uses the ball bearings. — Preceding unsigned comment added by (talk) 13:15, 24 February 2014 (UTC)

Nope, Rockwell can use either cone or ball depending on which scale you are doing. For example, HRC scale uses a cone but HRB uses an .062 ball. This is already explained in the article (look in the table in the Scales and values section). — ¾-10 17:48, 24 February 2014 (UTC)