Datums for Dummies

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You run people out of threads with your know it all comments that teach us little to nothing about how to solve the problems we are having.
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I did, I suggested you get a grip on datums, after reading your response I thought I was dealing with a child. And then HiBC gave me the feeling he was being left out, that was about the time he declared "But a Datum is what ASME Y 14.5 says it is". I do not describe a datum in lofty terms, a datum is a round hole. A datum with a radius on the edge of the hole has to be corrected with a standard or it has to be used as a comparator.

I am not infatuated with tools.

You come off like you think you are the master of the universe
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I am not the one that can not measure the chamber and I am not the one that can not determine the difference between the length of the chamber and the length of the case from the shoulder/datum to the case head when the bolt will not close. Elmer Keith was an expert like the black smith; it did not take Elmer long to look at it. I have no problem looking at something without wasting time. It would appear there are a lot of reloaders that resent that, I do not believe it is my problem.

There are reloaders that are desperate for attention, they have a problem with saying OIC as in OH! I see, or I understand, or thank you.

Knowing there are reloaders on reloading forums that will not allow anything past them I have offered to contact reloaders through the mail system and on the phone.

In my opinion you should avoid trying to use one member against another., again; am I the only one that notices.

F. Guffey
 
Someone scores an eight out of nine in this thread!
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It's not just this thread. There are many of them. I have a narcissist at work too. Nobody can have a conversation without some interjection about incorrect grammar or some minute error in what someone says. It is always a statement that points out inferiority and it is always condescending. A narcissist can never see their flaw because in their mind if they are not above everyone else they somehow less of a person. To have a flaw is unthinkable.
 
You guys should meet my brother. He claims he's so smart he knows what anyone he's talking with is thinking--2 or 3 steps ahead of them before they even say anything. He then will tell you that he knows what you really are thinking--not what you think you are thinking. I call him x-man.:D:rolleyes:
 
Mr Guffey,you said
ANSI 14.5 expert
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,suggesting I am the ANSI Y14.5 expert. I'm not. I do not claim to be.
I said I was one of (hopefully) over a million other people in the USA who are engineers,CAD designers,Machinists,inspectors,or who otherwise work in manufacturing,engineering,or related fields.

I offered ANSI Y14.5 as a definitive source for the reader to go look up the meanings of terms misused here.
My goal was to empower the reader. I hope the reader gains the power to correct me when I am wrong.

The other style might be to attempt to DISEMPOWR the reader.To make the reader "smaller"

That can only be done with the reader's cooperation.

You have your boxers in a bunch because some of us are not cooperating with you.

Bring something to the table besides a bellyache
 
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Aside from my feeble attempts to lighten the conversation with some humor and looking back at everything mentioned. I am not and never was a mechanical engineer, a tool and die maker or a machinist. However, over a career which spanned over 40 years I had the pleasure of working daily and interfacing daily with some of what I feel were the finest in the business.

The business of this forum is the shooting sports, I believe everyone here shoots something. Terms and definitions can take on different meanings depending on how they are applied and who is using them. Earlier I mentioned, as did others before me that if we have more than a single datum it would be data but that only would hold true for an IT (Information Technology) type using the terms, for example:

datum - Computer Definition. The singular form of data; for example, one datum. It is rarely used, and data, its plural form, is commonly used for both singular and plural.

I doubt that is what anybody here has in mind or has much, if any concern with. Sounds nice though. Moving along to ANSI with a focus on ANSI Y14.5 which over the years, like any standard has had updates and revisions but seems a constant on the definition of a datum:

A datum is theoretical exact plane, axis or point location that GD&T or dimensional tolerances are referenced to. You can think of them as an anchor for the entire part; where the other features are referenced from. A datum feature is usually an important functional feature that needs to be controlled during measurement as well. The GD&T for anyone who missed it is Geometric Dimensioning and Tolerancing. Now as to ANSI? ANSI (American National Standards Institute) is the primary organization for fostering the development of technology standards in the United States. ANSI works with industry groups and is the U.S. member of the International Organization for Standardization (ISO) and the International Electrotechnical Commission (IEC). The object here is standardization so when I look at a drawing and another looks at a drawing we both interpret the various symbols and terms in the same way. Actually before I retired I saw many of the new hires, right out of college referring more to ASME Y14.5M (American Society of Mechanical Engineers). The definition of datum remains the same.

Finally in the world of the shooter the standards organization comes out as SAAMI (Sporting Arms and Ammunition Manufacturers' Institute).
Creating and publishing industry standards for safety, interchangeability, reliability and quality.

Coordinating technical data.

Promoting safe and responsible firearms use.

SAAMI has a glossary of terms unique to the shooting sports and they choose to define datum as:
DATUM
A reference plane, point or diameter that provides a base for calculations and measurements.

That being pretty much in line with ANSI and ASME. As shooting enthusiast my suggestion is to run with SAAMI unless of course you want to start developing your own cartridges in which case ANSI and ASME might be worth your consideration so you can draw your new case in a way the next guy will understand.

Thank you and have a nice end to the weekend.
Ron
 
Thanks, Ron. That was a very good definition.

I hope that this thread may have gotten the things said that needed to be said and that we all might move forward from here. I feel ill from the negativity. Sometimes throwing up cures a sick stomach. I hope that this can be the end of negative exchanges.
 
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Let us understand something about narcissistic and psychopathic personalities. As we have seen, they are grandiose, self centered, manipulative, lacking empathy. They also don't have guilt or shame, so you will see all Guffey's nonsense, again, and again, and again.

I think it is his way to be the center of attention. He is the star, center stage, in the online epic play of his life, as we, the bit players, give him the audience needed for the adulation he so desperately desires.
 
Hey guys... Guffey's alright.
If it weren't for him, you'd only have me to kick around.
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Naw, you are well liked and respected. You explain your thoughts well so those in a learning curve can understand your points. :)

Ron
 
Thanks, Ron. That was a very good definition.

I hope that this thread may have gotten the things said that needed to be said and that we all might move forward from here. I feel ill from the negativity. Sometimes throwing up cures a sick stomach. I hope that this can be the end of negative exchanges
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.

We need to find someone that cares, I suggested you slow down, I suggested you avoid using one member against another. This forum is part of social media, I suggest you read through your responses and determine if you your responses are social or anti social.

F. Guffey
 
If I could block you from my threads there wouldn't be anything negative in any of them. You will obviously admit no fault. Would you then, please, not post comments in my threads? It would be greatly appreciated.
 
OMG...... will someone please delete this thread?
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Just click your heels.:D

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I offered ANSI Y14.5 as a definitive source for the reader to go look up the meanings of terms misused here.
My goal was to empower the reader. I hope the reader gains the power to correct me when I am wrong.
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There is no shortage of definitions, All of this started when reloaders failed understand how to use the datum and or how it applies to reloading. There is a most interesting story that came out of the time of Shakespeare. A big time land owner offered to share his dukedom with one of his subjects if one of them could perform a task that seemed impossible. As the story goes he held up his end of the deal.

The next time the story emerges was in the late '80s, those that got upset even though they were not asked to participate claimed it could not be done. I did appreciate the effort they made; I could not understand why their failure was my fault.

The datum is a round hole; the reloader has only to keep up with three datums. One is .375", another is .400" and the last one is .410". And then there are cases that are too small in diameter for the .375" datum.

For years and years reloaders thought the datum was located half way between the two shoulder junctures the 25/06, 270, 30/06, 8mm06 and 338/06 use the same datum, It would be impossible to have one datum if the datum was located half way between the two shoulder junctures.

No matter what lofty terms are used to describe the datum it comes down to how it is used, it seems there are too many reloaders that do not believe it can not be done. I use the term 'datum/shoulder', If I want to measure the length of the case from the datum to the case head I use the correct datum, the datum contacts the shoulder and at the same time locates the point on the shoulder the measurement if taken from. There are all types of improvements than can be made, most struggle with keeping the case square with the datum. That is the reason there are so many gages for measuring the length of the case from the shoulder to the case head.

One Canadian contacted me about making a gage, he said it worked but was awkward to use. I asked him if he drilled the .375" hole through the plate, and we all know he did and he said 'yes'. I suggested he start over with a hole that was the same OD diameter as the neck of the case and then drill another hole with the same center that measures .375", that would be a hole through the plate with two diameters. I suggested if he messed up make a bushing for the neck,

F. Guffey
 
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I think the age limit on this thread is 13? Sounds like a bunch of kids.

"Guffey, don't talk to me. Guffey, I don't like you."

If some folks would open their eyes and see what is in front of them, you could see that Mr. Guffey is a walking encyclopedia of gunsmithing knowledge. He just might have a conversation with each of you if you would PM of even call him on the phone. I know this from fact and personal experiences.

I honestly don't know why Unclenick has allowed that Guffey bashing to continue with 4 pages of posts.

I also believe that Steve started this thread for just this purpose. Excuse me while I go puke.
 
Alright-- I've learned from this thread that I really don't have a clue what datum, headspace or head clearance are. But let me suggest that "all is not what it seems"--and by that I think of critical case expansion parameters as having multiple axes--not just a linear one on axis with the bore.
 
The thread was posted to try to get the whole datum thing vented so it could end. It wasn't to bash anybody really. I was hoping that a purging might end the conflict. I got sick of reading "I am the only reloader who knows" instead of sharing what it is that is known.

By all means delete this thread. Hopefully some boundaries have been made and will be respected.
 
I honestly don't know why Unclenick has allowed that Guffey bashing to continue with 4 pages of posts.
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I included Unclenick, I said there are two members of this forum that have instructions for presses. One set covers the cam over press called the bump press and the other set of instructions that cover the non cam over press that is not a bump press.

F. Guffey
 
Unclenick has been tied up with work and barely a moment to be online this past couple of weeks. I will be happy to terminate the bashing now.
 
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