Proper terms for describing Hardness

marcusja2002

Involved In Discussions
A debate in my company has come up and I'm hoping the community can help me out.

I've been taught throughout my career when you describe hardness on a drawing you use the term "Hardness" then indicate the Number and the Scale or it's also acceptable for like rubbers and plastics to shorten it to 0075 or A75 as in Shore 00 or Shore A.

Some of my coworkers are using the term Durometer 75 with no scale indicated plus a material call out. and I'm believing this is wrong, but they are pushing back saying its ok because Silicone rubber can only be in the Shore 00 range for example.

Am I being too picky in asking for a full audit and update of the drawings or are they wrong because a material called out, doesn't necessarily lead you to a path of proper scale choice and the drawings should have further detail.

What is the industry standard way to call out hardness properly?

Thanks in advance.
 

Jim Wynne

Leader
Admin
I would think that at a minimum you would want to call out the relevant standard (ASTM D2240, e.g.) and the scale. Whether or not this is worth backtracking and updating drawings is a different question that no one here can answer for you. It might be enough to require the proper callout on new drawings and changing the specification on old ones when other changes are being made.
 

marcusja2002

Involved In Discussions
A durometer is a measuring instrument. I don't understand why they don't want to callout the actual requirement.
That's what I said. I made the analogy that they are saying "The side of this steel box is caliper 12" and his face got a little red and he just said thats not what I was taught. So for all I know there is a school of thought out there that teaches Durometer means Hardness, I'm just not familiar with it.

From the above comments, my gut is it has more to do with embarassement and time to audit and update drawings properly then be being wrong.
 

Jim Wynne

Leader
Admin
That's what I said. I made the analogy that they are saying "The side of this steel box is caliper 12" and his face got a little red and he just said thats not what I was taught. So for all I know there is a school of thought out there that teaches Durometer means Hardness, I'm just not familiar with it.

From the above comments, my gut is it has more to do with embarassement and time to audit and update drawings properly then be being wrong.
I have always been amazed at the number of engineers who don't know how to do their jobs when it comes to bullet-proofing a drawing.
 

Miner

Forum Moderator
Leader
Admin
I would check ASTM D2240 to be certain, but I worked 15 years in the rubber industry (20 years ago), and I believe that we used 55 Shore A.

We also used ASTM D 2000, "Standard Classification for Rubber Products in Automotive Applications", which encodes the hardness specification into the callout. D2000.png
 
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