INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Jobs

Good example of engineering drawing

Good example of engineering drawing

(OP)
Hi all,

I'm looking for a good sample part drawing done to Y14.5M.

Can anybody supply a drawing, or show me where I can download one?

Thanks,

ant77

RE: Good example of engineering drawing

The ASME Y14.5 specification has example figures of applying the tolerance to parts.  Isn't that suitable?

--Scott

http://wertel.eng.pro

RE: Good example of engineering drawing

That's a really general request. I can give you a drawing of a solid cylinder, it will have exactly 2 dimensions on it but it will be perfect to ASME Y14.5M-1994, or are you looking for something that correctly represents all aspects of ASME Y14.4M-1994 in a single drawing? If you are looking for a comprehensive drawing to base all other drawings off of, don't count on finding it. I have NEVER seen one that even comes close. You are better off just getting a copy of the standard. If you need to show someone what a Y14.5M drawing looks like, you will have better luck drawing one yourself.

Best of Luck,

David

RE: Good example of engineering drawing

The thing to consider before using only the standard is para 1.1.4 "The figures in this Standard are intended only as illustrations to aid the user in understanding the principals and methods of dimensioning and tolerancing described in the text.   The absence of a figure illustrating the desired application is neither reason to assume inapplicability, nor basis for drawing rejection.  In sime instances, figures show added detail for emphasis.  In other instances, figures are incomplete by intent.  Numerical values of dimensions and tolerances are illustrative only."

In other words, use the standard to understand the principals and methods, not as a bible for how a correct drawing will look.
I suggest checking out Tec-Ease or Genium for more valid examples, though they too will probably have similar limitations.

RE: Good example of engineering drawing

I would be happy to help you out, but I'm not allowed to send out dwgs. Sorry.

Chris
Systems Analyst, I.S.
SolidWorks 06 4.1/PDMWorks 06
AutoCAD 06
ctopher's home (updated 06-21-06)

RE: Good example of engineering drawing

I haven't seen a good drawing in ten years or so.

RE: Good example of engineering drawing

Ant77, you might be better off submitting a drawing that represents your best abilities at Y14.5 and have the group make comments / suggestions from there.  It may be daunting to face that kind of feedback, but it's an amazing learning opportunity for you, and you'll appreciate how difficult it is to get everyone to agree on a "compliant" drawing.

Jim Sykes, P.Eng, GDTP-S
Profile Services
CAD-Documentation-GD&T-Product Development
www.profileservices.ca

RE: Good example of engineering drawing

(OP)
Thanks all.  As one of you pointed out, examples in standards can be quite detached.  To get the full picture you really need to see, well, the full picture!

Yes, I would like to put a drawing before my other CAD managers and say "here is a drawing done to Y14.5M" and review it as a whole.

I have tried posting drawings here for critique before, but written feedback on a drawing has it's limitations - especially for visual people.

Perhaps somebody knows of a NASA, Boeing, automaker, or other institution's repository of drawings on the web (maybe parts that are put out to tender, or included in public specifications)?.  Or maybe you have seen a drawing used in a course or presentation that is freely available on the web?  Or do you have an old drawing you would be free to share?

Thanks,

Ant77

RE: Good example of engineering drawing

Dwgs from NASA or Boeing are not downloadable unless you work for a specific project and have access to it. Those employees can lose their jobs if they do it.
Also, most people have their interpretation of Y14.5. You need to purchase the spec and read it. I suggest going for training.
For us to send you a dwg, IMO, is not a good way to learn 14.5.

Chris
Systems Analyst, I.S.
SolidWorks 06 4.1/PDMWorks 06
AutoCAD 06
ctopher's home (updated 06-21-06)

RE: Good example of engineering drawing

Like Jim suggested, your best bet I think would be for you to post something and have someone redimension it. Are you working to another standard currently? Are you just trying to convince your boss to switch to the new standard? Unfortunately just showing someone a drawing that is produced to ASME Y14.5M-1994 is not a very good way to convince them to change, unless your current drawings are a REAL mess, and then the best way is to show them how much cleaner the drawing would be after applying the standard.

RE: Good example of engineering drawing

Along with aardvarkdw's comment, people (managers in particular) need to become educated about the value and impact of GD&T as a whole.  Otherwise, it won't matter how clean the drawings look to them; pretty drawings don't sell product and they will reject the changes.

Jim Sykes, P.Eng, GDTP-S
Profile Services
CAD-Documentation-GD&T-Product Development
www.profileservices.ca

RE: Good example of engineering drawing

(OP)
OK.  So my biggest problem with our current office drawing standard is the way we dimension symmetrical parts.  I have created a PDF document showing how we currently do it, and how I 'think' it could be done.  How do I post the PDF to this group for review?

RE: Good example of engineering drawing

(OP)
Thanks aardvark.  I've uploaded the files to tinypic.

Our current standard for dimensioning symmetrical details about a centreline is this:

One approach I'm considering is this:

I welcome your feedback everyone, thanks.

Ant77

RE: Good example of engineering drawing

Why not use the standard symmetric symbol? I have never seen =40.00= before. I would have never guessed what it meant.
I suggest getting a copy of Y14.5.

Chris
Systems Analyst, I.S.
SolidWorks 06 4.1/PDMWorks 06
AutoCAD 06
ctopher's home (updated 06-21-06)

RE: Good example of engineering drawing

I would advocate using a Datum to define your centerline.  One could question what exactly sets up the centerline.  Is it the holes 20 mm apart, holes 30 mm apart, holes 40 mm apart, the outside edges of the part, etc...?  I would consider calling out the outside edges (this is what I assume your centerline is defined by) as a datum.  Then place a true position tolerance on all the hole dimensions relative to the datum defined by the outside edges.

RE: Good example of engineering drawing

How can all dimensions be symmetrical about the centerline?  What about the vertical dimensions.

RE: Good example of engineering drawing

[IMG]http://i10.tinypic.com/4h83dzt.jpg[/IMG]

This is how I would do this. The equal signs on the ends of the centerlines are as per ASME Y14.2-1992 sect. 2.7, and Fig.1 and are the approved method for denoting symmetry. This is referenced by ASME Y14.5M-1994 sect. 1.8.8 . There is no need for a note and there is no need to dimension both sides. You could get away with only showing one side of the part if you wanted.

David

RE: Good example of engineering drawing

aardvarkdw ... wouldn't that style of dimensioning effectively double up the tolerance of the hole positions?

cheers
Helpful SW websites FAQ559-520
How to find answers ... FAQ559-1091

RE: Good example of engineering drawing

Please read what I suggested, it would cover the positional tolerance issue nicely (I think) and make it obvious as to what establishes your centerline.

RE: Good example of engineering drawing

CBL,

You may be right, but that really wasn't what I was intending to demonstrate. Depending on what sort of tolerance is required, you may want to dimension between the holes like Ant showed in his post, but the method of showing Symmetry is sound.

Pdybeck,

Being as I don't know how the part is to be used I didn't include datums and such. I was just trying to show the ASME Y14.5M-1994 method of denoting Symmetry.

RE: Good example of engineering drawing

Greetings,
I recommend you take a look at the Drafting Manual Pocket Companion. You can find it on the Genium Drafting Zone site. I have been providing these to designers and engineers for years. There are good examples of GDT, delineation, hole callouts, often used formulas and tables etc. It's all based on ANSI.

RE: Good example of engineering drawing

I would establish your 3 primary datums as the face of the part (A) and two perpendicular sides (B and C). then use basic dimensions from B and C to locate your holes, using a positional tolerance (value of which determined by need) to A, B and C.

RE: Good example of engineering drawing

ant77,
Please read FAQ559-1100.
Your picture makes all posts cut off the right side. I can not read everything.
Thanks.

Chris
Systems Analyst, I.S.
SolidWorks 06 4.1/PDMWorks 06
AutoCAD 06
ctopher's home (updated 06-21-06)

RE: Good example of engineering drawing

I think some of the responses are getting a bit off-topic.  The original question was regarding how to dimension in Y14.5M, not whether the method used was legal or consistent with any other standard, whether or not such standard is referenced within Y14.5M.

I've posted a (hopefully) clean drawing for ant77's geometry on my site http://www.profileservices.ca/files/tidbits/tidbits_missc.html; download it and review it with the following text:  

Where to begin ... with datums!  The most fundamental benefit of GD&T by ASME Y14.5M-1994 or any other standard, is that you can repeat the inspection process because you have datums to establish the origin of measurements.  Your likely Primary Datum (let's call it Datum-G) will be the back face of the U-channel.  This is better than the two feet of the channel because it minimizes the effect of warpage in the center panel.  Put a Datum-G symbol on the back face or on a leader from that face (see Y14.5M-1994-Fig. 4-2, Datum-D, -E, -F).  Next, the symmetry is visually about the centerline, so that is the desired location of the Secondary Datum (let's say Datum-A).  To do that, put a Datum-A symbol inline with the arrow of the dimension line (see Y14.5M-1994-Fig.4-19, Datum-A or Datum-B).  This indicates that the mid-plane is the datum feature, and that is where the locations will be measured from, and hopefully where the features will also be dimensioned from.  The Tertiary Datum should be the face from which the 10,20,30 dimensions originate; label it as you would for the Primary Datum, indicated above, but call it Datum-K.  

As the symmetry is visibly about the centerline, you do not dimension both of the symmetrical holes, just the location of one of them, with the dimension starting at the centerline (per Y14.5M-1994, if features on a workpiece appear to be symmetrical, they are assumed to be symmetrical, and those features not complying with a symmetry would need to be individually dimensioned).  You will also need a Positional Tolerance on the 6X Dia2.50 callout (drop "HOLE").  A diametral tolerance zone of whatever tolerance size would be applied wrt Datum Reference Frame [G|A|K].

Of course, overall dimensions are needed, and a general tolerance covers all features not otherwise directly toleranced.  Note that the trailing zeros are omitted and the C/L symbol is also omitted.  You need to indicate the dimensioning standard under which the drawing was created.

Jim Sykes, P.Eng, GDTP-S
Profile Services
CAD-Documentation-GD&T-Product Development
www.profileservices.ca

RE: Good example of engineering drawing

MechNorth,
My understanding of establishing datums is that they "shall not be applied to centerlines, centerplanes, or axes", as these are not true features.  How is it allowed in this case?

RE: Good example of engineering drawing

ewh,

   The datum A in Jim's example is not the centerline.  The centerline is defined by Datum A surfaces, which are the edges of the part in this example.  This is a key difference and is defined under ANSI Y 14.5.  The same would be true for placing a Datum on a diameter.  The actual datum surfaces are the cylindrical surfaces and they are used to set up center planes which can be referenced by other features.  That little centermark that we all place on our drawings for cyclindirical features is a theoretical intersection of planes that are defined by the outside edges/surfaces.  I agree with Jim's approach to this drawing and was as I suggested (for establishing Datum A at least).  We use this method on our machined casting drawings where we desire a set of machined holes to be centered within outside features of a casting.  The drawing is correct to ANSI Y14.5 and is clean and concise to all our personnel who use the drawing.

RE: Good example of engineering drawing

pdybeck,
You are right.  I was just starting to post a "nevermind" but you beat me to it.  I had posted before I looked at the example.

RE: Good example of engineering drawing

Based on my post I may not be the best to nit-pick but shouldn't all the dims that locate the holes be basic as well?

RE: Good example of engineering drawing

aardvarkdw,

   Good catch, they should be basic.  I would also dimension between holes and not from center of the datum reference out to the hole.  So you would see 20, 30, and 40 dimensions between holes and they woud be basic.

RE: Good example of engineering drawing

... and shouldn't the hole centerlines be connected horizontally (or the dimensions be appended with 2X)?

RE: Good example of engineering drawing

Ant77,

If your company has a drawing standard tha is referenced on your drawing, it might sork for your case.  However I doubt that lacking that, there would be anything close to a universal interpretation.

RE: Good example of engineering drawing

In answer to the original post:

You could also look at something like the Genium manual which expounds upon Y14.5 & associated standards.  Again though it's specific examples more than full drawings.

www.draftingzone.com

However maybe the applied suggestions to your sketch are more usefull.

RE: Good example of engineering drawing

The hole-locating dimensions are basic, as indicated by the note "NON-TOLERANCED DIMENSIONS ARE BASIC".  This is very common, and reduces the workload a bit (see Y14.5M-1994, Sect. 1.4-a, and Fig.5-1(c)).
You could dimension one hole from the other, but the typical and common method is to dimension from the datum (in this case, represented but not physically embodied by the centerline) to reduce math errors in programming or machining.  Similarly, you can connect the holes by centerlines, but it's not necessary and can lead to a very messy drawing (I had a situation where 144 pattern locations pitched 60mm apart were on a single plate about 1.5m x 1.5m, with 5 holes per location ... that's a lot of centerlines covering the page).  Again, if the features are visibly symmetrical about a common and obvious centerline, you don't need to go any further than that.  As a result, you don't need to add 2X for each of the lateral dimensions either.  
In a previous work environment, we focused on minimal detailing as a cost-savings measure.  While I didn't agree with everything that was done under that label, it was fairly obvious that anything that legitimitaly reduces detailing time and the risk of mistakes adds value to the engineering.  It's not incorrect to add the extra dimensions, center-lines or quantities, but they add work and increase the risk of making a mistake (e.g. quantities).  As a side-benefit, detailing the "odd" features that don't meet the symmetry will make them stand out and reduce the likelihood of being overlooked.

Jim Sykes, P.Eng, GDTP-S
Profile Services
CAD-Documentation-GD&T-Product Development
www.profileservices.ca

RE: Good example of engineering drawing

In answering to the original question: According to the freedom of information act, you can get standard drawings on everything from Apollo to Atlantis. I have a copy of the details and specs regarding the Shuttle. All I did was ask. No body gets in trouble, They want thier information in a certain format and they provide a standard outline. Just as ANSI, FAA, NASA, FEMA. Pretty much anyone who utilizes consultants provides guidelines and examples of what and how they acccept the final product.
Have Fun Out There,
Regards,
Namdac

RE: Good example of engineering drawing

MechNorth,
Seems like good reasoning to me.  Old habits die hard though.

RE: Good example of engineering drawing

I hear ya, ewh.  I resisted GD&T for a while, even when I was put in charge of it...little by little, and a whole lot of studying, applications and mentoring, I got there.  The plate I described was a nightmare for design & manufacturing, not to mention inspection.  People were convinced that I'd redesigned and simplified the plate when I cleaned up the drawing and circulated it with minimum dimensions & reduced clutter.  To loosely mis-quote former Canadian Prime Minister, Jean Chretien, "The proof is the proof...when you have the proof, you know it is the proof, and there you have the proof."  

Jim Sykes, P.Eng, GDTP-S
Profile Services
CAD-Documentation-GD&T-Product Development
www.profileservices.ca

RE: Good example of engineering drawing

Ant77,

One other question please.  Is interchangeability a requirement for this part?

RE: Good example of engineering drawing

(OP)
Thanks everyone for your feedback!

Firstly, apologies to you all for the large JPEGs in my post - please put this down to me being a first timer.

MechNorth, thanks for all your feedback and the sample you posted.  This is exactly what we needed to see, and as you say it takes a lot of studying and mentoring to get to that level, so your feedback is very valuable.  

I agree with pdybeck that seeing the actual distance between the hole centers would feel more 'natural'.  What would you do on the drawing if you wanted the hole centers inspected, because the 40mm hole centers on this part match a 40mm hole centers on a mating part (or is this a naieve question?)

I love the note 'non-toleranced dimensions are basic'!

Unfortunately Ringman our company is not large enough to have it's own documented drawing standard, hence our need to rely on published standards.  This part is not interchangeable.

RE: Good example of engineering drawing

ant77,
The datums and feature control frame establish how to set up the workpiece for inspection.  That's a little beyond this lesson.  Are the 40mm holes clearance holes (for a screw fastener) or a tighter fit as for dowels?  If the entire assembly is located based on those two holes, then the datums can be changed to reflect that, but it won't make much difference if the holes are a loose fit.

Jim Sykes, P.Eng, GDTP-S
Profile Services
CAD-Documentation-GD&T-Product Development
www.profileservices.ca

RE: Good example of engineering drawing

(OP)
In this case the holes are screw holes for mounting another part.  Exact alignment of the other part is not critical, so no alignment pins are used.

RE: Good example of engineering drawing

The positional tolerance value would be set according to the needs, as would the size tolerances (the numbers in my sample drawing were just randomly selected).  There are formulas to determine optimal values based on tolerance analyses.  You should have enough to start with now.  Good luck.

Jim Sykes, P.Eng, GDTP-S
Profile Services
CAD-Documentation-GD&T-Product Development
www.profileservices.ca

RE: Good example of engineering drawing

(OP)
Thanks Jim.  One last question for now.  Do you use GD&T for everything you design, or just machined items?  I had a quick look at the closure details on your website and noticed a different dimensioning style.

We design a lot of plastic injection moulded parts, and I was wondering if GD&T was appropriate?

Thanks.

RE: Good example of engineering drawing

I use GD&T whenever the client or manufacturing system can handle it or are interested in learning it.  The thread specs on the site are part of an industry standardization project that I participate in.  Unfortunately many of the participants aren't up to speed on GD&T, so they aren't sure if they're ready to make that leap yet.  GD&T is, however, amazingly useful for injection molded articles as it provides an easier/better way to account for warpage allowances, etc.
If you're thinking of moving your company into GD&T, I'd suggest getting a consultant or training supplier in to talk things over and help you build your case.  You can check out some of the other threads on Eng-Tips for GD&T Classes from a number of training suppliers that users recommend.  I've had such discussions with Don Day at www.tec-ease.com, and Greg Hetland at www.iigdt.com.  Another EngTips user, Curtis DeSaele (ragtop1955) (www.GeometricSolutions.net), provides training, and I can help with GD&T implementations as well.  Good luck, and let us know how it works out.  
     wavey

Jim Sykes, P.Eng, GDTP-S
Profile Services
CAD-Documentation-GD&T-Product Development
www.profileservices.ca

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close