tired of bad drawings 4

[duk748]

hello - sorry for a monday mourning rant but here goes - last friday i brought a drawing to the attention of our engineering supervisor that had every dimension on the drawing as basic - datums taken from odd surfaces, incorrect use of true position & tolerances between holes set to .001+/- which are not required - i had suggested to change the drawing to correct the mistakes which were very obvious to someone w/ gd&t training or even good drafting skills - i was told to leave the drawing alone & make no change because the shop would look at the drawing & know to pay a little extra attention when making the part - i was at a loss for words as to why things like this are let go almost regularly & we keep from teaching people in the work force the correct way to do things - i ask how inspection was to check this part & just got a fluff answer w/ a deer in the headlights look - how do people work in engineering for so many years at so many jobs & continue to fly blind & not take responsibility for their work - i had to learn the right way why is it acceptable for some to just get by - now i can have my coffee - have a great week ahead

 

[mkcski]

I totally agree with CH. Unless you want to start a personal library, get the boss to pay for them and get of ALL of them.

 

[natepiercy]

Thanks for the advice, all.

Kenat,
That's not a specific example, you're right that things like missing dimensions or lines would be worth more. I just threw together a list of more nitpicky things and threw point values at it to add up to 15 to give an example. If I was to start building a personal library, would 14.100 or 14.5 be the best starting point? Also (admittedly straying quite off topic) as an ASME member, am I eligible for any kind of discount on standards? Or does everyone pay the same price for these?

Mkcski,
Thank you for your recommendations! I just got the thumbs-up to buy the 2009 collection.

 

[mkcski]

natepiercy:

There is no "2009 collecdtion" Each standard has its own revision year.

If your drafting skills are not up to snuff, I would get 14.2 first, then 14.3, 14.5. Get 14.41 if you are communication in the electronic 3D-model world and not traditional 2D drawings. Forget 14.100 - very management oriented synopsis. I have heard of the "Genium Drafting Manual", but have never seen it- might be worth investigation.

 

[KENAT]

As an ASME member I believe you get a discount but they are still quite expensive - I'd seriously look at getting your mgmt to pay if at all possible. I think you may be able to buy as a complete set - not 100% sure.

I'd disagree with mkcski, while 14.100 is fairly high level 'list of standards' for much of its content there are some nuggets in there not covered elsewhere. Especially if you decide to use the non mandatory appendices for guidance - I actually refer to it about as much as any other standard except Y14.5.

Y14.5 is the one I use most but... it is focused on dimensioning & tolerancing and there is more to good drafting than just that.

If your CAD has a canned ASME style setting then you probably won't get much out of Y14.2 so I wouldn't bother with it, and unless you are revising/setting up your templates not sure how much you get out of Y14.1.

For 'general drafting' I'd pick Y14.3 & Y14.24.

If you do castings, forging or molded parts then I'd say Y14.8 is virtually a must.

Y14.34 & Y14.35 also get to be useful on occasion.

Posting guidelines faq731-376

http://eng-tips.com/market.cfm?

(probably not aimed specifically at you)
What is Engineering anyway: faq1088-1484​

 

[mkcski]

natepiercy:

I rarely refer to 14.100, but after reading KENATs' comments, he is correct and I agree you should buy 14.100 too.

 

[Korichnevijgigant]

I feel your pain, I wish I could share some of the trash that previous "designers" have made that are released and controlled now by customers so I just have to roll with them.

Its insane.

There was a part that was made to fit inside this assembly. I looked at it and all the dimensions were basic, no criticals or tolerances, AND to top it all off, the dimensions were not taken from the interface surfaces. I brought it up to my boss and said we needed to do an ECN on the drawing because we would have issues, I was told, no no dont worry its fine.

So they had one made and guess what? It didnt fit...

 

[natepiercy]

mckski:
I should have clarified - I was given approval to purchase the Y14.X 2009 collection of "The GD&T Hierarchy" plus workbooks, answer manuals, and pocket ref.

So you both agree that 14.5 is the most useful to start with, if we're only purchasing one at a time? Followed by 14.100, then 14.3? I wasn't kidding when I said "small company" - it's just the three of us. I'm guessing that I'll have more luck asking for smaller packages over a dispersed period of time. We have a weekly meeting and we set aside some time to do knowledge sharing, and I know we will all see the benefit of taking that time to review (or teach) some best practices based on the ASME standards.

 

[KENAT]

14.5 covers the dimensioning and tolerancing, which is arguably the heart of what most mechanical drawings need to communicate.

I'm a bit dissapointed you jumped to getting the training material etc. rather than the actual standards given what several of us posted but it'll probably work out. The standards by themselves can be a bit dry & in 14.5's case overwhelming.

Posting guidelines faq731-376

http://eng-tips.com/market.cfm?

(probably not aimed specifically at you)
What is Engineering anyway: faq1088-1484​

 

[mkcski]

natepiercy:

In response to KENAT's last post: I agree 14.5 is the DICTIONARY for reading and writing GDT? Ideally you should have 14.5 in front of you and then read the training info and compare the interpretation in the training to the words in the spec.

 

[natepiercy]

Ah. That makes a lot of sense, actually. I was looking for any and all recommendations for a starting point, so the first title I got that was up my alley was what I set my eyes on.

 

[mkcski]

natepiercy:

Over time I would recommend you purchase as much/many training "books" as you can to get different and better examples of GDT applications and their interpretation.

Alex Krulikowskis' materials at ETInews.com are comprehensive. Al Neumann and Bruce Wilson also have web sites, as will as many others. As I mentioned earlier, my personal favorites are Don Days materials at Tec-Ease. The pictorials are really good and in color!

 

[3DDave]

The problem with training materials is seen in the progression of learning to program:

Step 1) Person is introduced to the concepts.
Step 2) Some examples are seen. (seeing the basic (pun!) symbols)
Step 3) Person tries simple program that is evaluated by non-biased computer/software. (understanding the grammar)
Step 4) Repeat 3 until program meets expectations. (understanding basic tolerance analysis)
Step 5) Practice increasingly complex programs evaluated by non-biased computer/software.
Step 6) Repeat 5 until programs meet expectations. (understanding medium tolerance analysis)
Step 7) Learn to analyze software written by others (understanding complex tolerance analysis)
Step 8) Learn to generate programs that write other programs (creating tolerance schemes to match variation limit requirements)

What is usually missing is everything at step 3 and after. The only non-biased computer I've come across for dealing with D&T was the software from VSA. It was easily checked to see that its analysis conformed to Y14.5 and produced results that should be expected from the dimensioning and tolerancing scheme applied by a compliant factory.

For most people it's like learning to program by asking other people what they think a program will do when none of them has had access to a computer. While it's possible to do, the rate of success is going to be low and the rate of people believing their own incorrect answers is high. The lack of a standard, unbiased method of evaluation continues to be a problem with people creating and sticking to incorrect and sometimes outlandish interpretations.

Most training materials are stuck at step 2. If there is low-cost, easy-to-use software that clearly demonstrates the effects of tolerance schemes it would be good to know. VSA and Sigmetrix aren't in that category, however good they are.

 

[mkcski]

3DDave:
I agree that "talking heads" in GDT videos are boring and do not provide motivation to understand concepts. I was very fortunate to have a mentor at my place of work in the 1980's. He was a great teacher. After I caught up to his level, we both advanced our understanding by attending seminars presented by Y14.5 committee members at our place of work and at "engineering" conventions. We continually picked the brains of these "experts" via fax and later email.

Natepiercy: Given my experiences, I highly recommend you find a mentor and attend seminars presented by a real person! Plus using this Forum as a springboard !!!

 

[natepiercy]

mkcski: How did you find out about these seminars? Were these generally sponsored by an organization such as ASME or a company?

 

[mkcski]

natepiercy:

Get on the ASME web site and look for GDT "classes" sponsored by ASME. The ones I attended in the 80' and 90's were at ASME conventions held throughout the year (so members can present papers and vendors can show their wares).

I am currently signed up to attend a "stacks" seminar at Effective Training Inc (ETI)in Lavonia, MI ETI is a SAE division. They have many classes available.

Tec-Ease also has classes. I attended a "what's new in 2009" seminar run by Don Day at a Y14 committee meeting in 2010. He is very dynamic but I am not sure he is still presenting.

At great cost, you can pay an "exert" to come to your office/plant. The company I work at in the 80's had Al Neumann come for a whole week and run 2 sessions each day. I learned and unlearned quite a bit.

 

[3DDave]

Don Day is no longer presenting as he passed away recently.

http://www.chautauquatoday.com/obits/details.cfm?id=23385

The underlying problem isn't the difficulty of learning the material, it's that those who don't care to learn it have an opinion and do care to share it. Hence the need for a non-person evaluation.

D&T has been around for more than half a century, but it is generally poorly used because of the pulled-from-the-... analytical ability of the 95% who think they know something because they got to what I numbered as stage 2. I doubt that anyone would hire a programmer with the same stage 2 credentials (though I've read enough Daily WTF to know that doesn't stop idiots with opinions commenting on software; not the commenters on DWTF who are hilarious, the people they work with/for.)

 

[mkcski]

3DDave:

Thanks for the update on Don Day. I was following his blog on and off for years and all of a sudden it ended. Now I know why. This is a great loss for him family, friends, the GDT community and to advancement of the "technology".

I totally agree with your comment "those who don't care to learn it have an opinion and do care to share". I have run into many "expert" students in my intro class who argue the definitions even after I read them word for word. They refuse to believe they have been doing it wrong - incorrectly inspecting flatness (as parallelism) is a classic - and that they need to unlearn some things. Oh well.

My problem for many years was the lack of an "official" test to give some creditably to those who do know GDT. Finally in the 1990s the test arrived. I was somewhat disappointed after taking the test (in 1999) that it mainly required one to regurgitate the standard and there were too few "analysis/calculation" type of questions. Anyway, from my travels, testing in this subject is one of the hardest things to do fairly.