34 Replies Latest reply on Jul 11, 2017 7:26 PM by Dennis Dohogne

    How's my drawing?

    Eric Eubanks

      Mainly the title block. Is there anything not filled out that should be? it's hard to understand what a lot of that stuff means.

      pressure.PNG

          • Re: How's my drawing?
            Eric Eubanks

            What indicates that that dimension needs a tolerance?

              • Re: How's my drawing?
                Dan Pihlaja

                ALL dimensions need tolerance.   You need to indicate to the manufacturer what range is acceptable for that particular dimension.  Leaving out the tolerance either means:

                1) that the part has to be absolutely perfect to the microscopic level or

                2) means that the manufacturer can make up his own tolerance.

                 

                For # 1, this is impossible.  Period.  I don't care what manufacturing process you use, it won't be perfect.

                For # 2, this is dangerous.  The manufacturer doesn't know the design intent behind your part, not what it mates to.

                 

                In that little box at the bottom, you have a general tolerance area.

                 

                You need to at least fill that out.  Then make your dimensions have the same number of decimal places.

                 

                In our drawings, a 3 place decimal means that the dimension has a +/-.005" tolerance on it.   Using the general tolerance allows me to make most of my dimensions at 3 decimal places and leave off the tolerance for each dimension.  When I want something tighter (or looser) than that, then I specify it on that particular dimension.

                 

                Be aware, the tighter the tolerance, the higher the cost of manufacturing the item.

                  • Re: How's my drawing?
                    Steve Calvert

                    Dan Pihlaja all dims don't need a tolerance for two reasons.

                     

                    1. Could be using GD&T
                    2. Could be using a tolerancing Spec like ISO 2768

                     

                    Steve C

                      • Re: How's my drawing?
                        Dan Pihlaja

                        Steve Calvert  wrote:

                         

                        Dan Pihlaja all dims don't need a tolerance for two reasons.

                         

                        1. Could be using GD&T
                        2. Could be using a tolerancing Spec like ISO 2768

                         

                        Steve C

                        I understand what you mean, and I suspect that you wrote this because I didn't fully define my post.

                         

                        ALL dimensions do need tolerance (except reference dimensions, but an argument could be made that you can stack up non reference dimensions and get the tolerance for the reference dimension).

                        But this doesn't necessarily mean that the tolerance needs to be shown at the dimension level.

                         

                        GD&T is simply a different way to tolerance something.  As an example, if you put a position tolerance on a hole, then the dimensions that define the location of that hole are basic.   Those dimensions now show the virtual location of the perfect hole.  This ultimately means that the tolerance for those dimensions comes from the position tolerance frame.

                         

                        Using a spec also applies tolerance to dimensions.

                         

                        This is exactly the point that I was trying to make in my post above.  In Eric's drawing, there is no tolerance spec, there is no Geometric dimensioning spec, there are no general tolerances called out and none of the dimensions have a tolerance applied to them.  The point that I was trying to make was that something needs to be applied to them.  They can't be perfect.

                         

                        Sorry if I was misleading. 

                • Re: How's my drawing?
                  Chris Saller

                  Do you know which standard you should be following? ISO or ASME or ? ...

                  Check out ASME_y14.1 for the drawing format size and layout.

                  • Re: How's my drawing?
                    Steven Mills

                    Two other title-block items that I would add.

                     

                    1. REV, the first one should be A, or 1 or 0. Then each time you make changes to the drawing, you up the revision level. Also make this tied to a drawing property as you may add more sheets later, and you want the same revision level across all the sheets to avoid confusion.

                     

                    2. Also add a line that tells exactly where the drawing is saved and it's file name on the computer would help. If you only have a hard copy later, you don't have to trawl through your computer files trying to find it's digital copy again. This also can be linked to a drawing property, and I think it's two of the auto-made ones, see pic below. A note linked to folder name and file name makes this automatically updated.

                    • Re: How's my drawing?
                      Dan Pihlaja

                      Eric Eubanks , I just wanted to point out:

                       

                      I hope that you are not taking any offense at anything posted here.   I wish that I had had to courage to do what you are doing when I was starting out.  Having a checker for your drawings cannot be undersold.

                      I was too much of a wimp to ask people about my drawings.   For some reason I was afraid of constructive criticism.  That, and I was overconfident.   Murphy's Law has taught me a few things. 

                       

                        • Re: How's my drawing?
                          Eric Eubanks

                          I appreciate the constructive criticism. I haven't taken offence to anything here.

                           

                          I just wonder if anyone else struggled as much as me. I have two teachers and both of them act like I'm terrible compared to the other students. One is especially condescending towards me. The other is more focused on architecture so solidworks isn't what he's best at, but he doesn't make me feel like an idiot every time he talks to me. That's the main reason I came to the forums for everything.

                            • Re: How's my drawing?
                              David Nelson

                              I have to wonder does your college have set classes for a degree in drafting.  If they do are you following in the order they have.  If they do not then your instructors need to do a better job.  For me I was working on a time table and took some of mine out of sequence those were the classes I struggled in.

                               

                                But for me My Architecture instructor taught Solid work and Revit.  He also taught AutoCAD for Architecture.  My Drafting standard instructor only knew AutoCAD.

                              • Re: How's my drawing?
                                Dan Pihlaja

                                Eric Eubanks  wrote:

                                 

                                I just wonder if anyone else struggled as much as me.

                                 

                                My stint into design and drafting was driven by something higher than me.

                                 

                                When I was in 9th grade, I broke my right arm.   Well, I had a machine shop and welding class at my high school, and since I had a right arm that couldn't bend, I was pretty useless there, not to mention if I accidentally dropped a slug of hot metal under the cast....WOWSA!!

                                The teacher for that class was also the resident AutoCAD teacher, so he dropped me in front of an AutoCAD tube and told me to play with it.   So, for 6 weeks, I got to play with it....nothing assigned, just trying things out at my own pace.

                                Then, my Sophomore and Junior years in high school, I pretty much ignored CAD.   My senior year, I took his AutoCAD actual class and was bumped into the "advanced" learning class because I got to play with it 3 years before LOL.  Looking back on it, it wasn't very advanced, but what can you do at a High school in 1995 with a limited budget for these kinds of things.

                                 

                                Then I went to Michigan Tech University and started for my Mechanical Engineering Degree.   We didn't do much for CAD while I was there.  A little bit of board drawing and a little AutoCAD.  That was about it.  It wasn't seen as something really needed at that point.

                                Needless to say, I made some extremely poor choices after about 2.5 years there and had to drop out.  So I pretty much resigned myself to working at the lumber mill and the farm for the rest of my life.

                                 

                                Then my uncle called me and said that a company near Lansing, MI was hiring drafters off the street and training them.  He told me to move down and apply.  So I did.  I got the job, and that started my crash course in I-DEAS from SDRC (didn't actually go to any classes, it was "on the job" training).  After 2 years, they sent me to Disney World in Florida to a conference for the new version of I-DEAS.  While I was there, I "happened" to sit down next to 2 Yoopers who were also at the conference.   They were originally from the U.P., but later moved to the Traverse City area.

                                 

                                I must have impressed them, because, 6 months later, they offered me a designer position at their automotive facility.  I worked with I-DEAS until Ford switched to CATIA V5 and did another crash course in CATIA (again, no classes, except an on-site VAR introduction...just "on the job" training).

                                I worked there until they closed their doors in 2008 due to the economic downturn.

                                Then I got a job offer working for a company that makes Gas masks near here.   Back to I-DEAS, until they switched to Solidworks in 2010 or 2011.  Then my life changed drastically (I will share how in a message if you want to hear it, but not this publicly) and I decided that I needed to be closer to home (the gas mask place was 45 miles from my house).

                                I got another job offer with my current employer (6 miles from my house) who solely uses Solidworks in 2012.  and I have been here ever since.

                                 

                                So, did I struggle?.....yes, but in a different way.  Keep on keepin' on!!

                                Revelation 3:8

                            • Re: How's my drawing?
                              Bernie Daraz

                              Eric,

                              As Dan mentioned please do not take offense here. I think everyone covered the tolerance issues and I would like to add as a question. Made from steel? The small radius at the bottoms of the 'tubes' will be a bear to manufacture. If the part is molded there is no draft specified on those 'tubes' or the through holes. Good luck with this and keep us in the loop!

                                • Re: How's my drawing?
                                  Eric Eubanks

                                  Is there a better material? I just thought a pressure plate would be made of steel.

                                    • Re: How's my drawing?
                                      Bernie Daraz

                                      Eric, Sorry but I can't speak to that. I was just wondering because I knew how difficult it would be to machine that item given all the radii in steel. I see a machining program that has a roughing cycle or more than one, followed by a finishing cycle. And again, possibly more than one. I'm probably wrong because I don't know what this is for, what loads, etc.

                                       

                                      I believe I mentioned draft, again noting we don't know. I don't anyway. Good luck!

                                  • Re: How's my drawing?
                                    Dwight Livingston

                                    Eric

                                     

                                    If you are using ASME metric, you should eliminate trailing zeros in most cases, per ASME Y14.5. A metric dimensioning system does not support a general tolerance based on decimal places. You can use an ISO tolerancing scheme as mentioned in another post, or apply a single general linear tolerance and add specific tolerances as needed, which is what I do.

                                     

                                    Also, you should state what standard the drawing uses. Here is an example of our general tolerance, as shown in our tolerance block.

                                     

                                     

                                    Dwight

                                    • Re: How's my drawing?
                                      Eric Eubanks

                                      Here's an updated version.

                                      Also one question. If I have to revise it because the first draft was wrong do I have to change the revision number or is that only if I want two different versions of a correct drawing?

                                       

                                      ansi.JPG

                                        • Re: How's my drawing?
                                          Dennis Dohogne

                                          Revisions are issued for when a production version changes from a previous production version.  Since you are still just working on your drawing no revision change is needed (unless you already released a version).

                                           

                                          Your drawing still shows first angle projection of the section.  Did you change your drawing to ANSI (Go to the drawing then go to Options -> Document Properties -> Drafting Standard.

                                        • Re: How's my drawing?
                                          Eric Eubanks

                                          ansi.JPG Here's an updated version. Third angle this time.

                                            • Re: How's my drawing?
                                              J. Mather

                                              I see a number of issues, but in this response I am going to concentrate on some of my pet peeves.

                                               

                                              1. Indicated in the blue ellipse - turn off the visibility of the origin.  (ask if you don't know how to turn that off)

                                              2. Have you ever used hand-held calipers?  If the answer is no, you should request your tuition back.  If it is yes, do a mind exercise (you don't have to physically do this, but you might try) - "How would you use your calipers to measure the 124 dimension on the right?"

                                               

                                              3. Based on thought exercise in #2, how would you measure (in the real world on the real part) the 52.98 dimension and maybe more important, how would you control that in manufacturing?

                                               

                                              4. See #3, but in addition - I refer to my students this issue as the, "Can't you see this issue?"  Let's send you to have your eyes checked!  Final step is a once over aesthetic quality check of the drawing.  Notice how the arrowhead of the 44.50 leader is right in the middle of the dimension text.  Does that appear aesthetically pleasing?

                                               

                                              Well, I add a couple more -

                                              holes are dimensioned in their circular view and cylinders in their rectangular view.

                                               

                                              Calipers.png

                                                • Re: How's my drawing?
                                                  Dennis Dohogne

                                                  Eric Eubanks, we applaud your efforts to learn.  I join others in not being impressed with your instructors.  Personally I am very impressed with J. Mather and would frankly like to see his course materials (for the purposes of training others I run into as well as bolstering my own knowledge).  I ALWAYS look forward to his responses.

                                                   

                                                  I'll add some advice to his comment.  Take your drawing and start a new part.  Make the part only from this new drawing.  You will learn very quickly if you have enough information on the drawing to tell someone else how it is geometrically defined.  (In this case you don't, but you should still do this exercise.)

                                                   

                                                  J. Mather, can you recommend a good resource (book or website) that can shorten Eric's efforts to learn what makes a good drawing?

                                                   

                                                  Eric Eubanks, what resources are you already referencing?

                                                  • Re: How's my drawing?
                                                    Eric Eubanks

                                                    I have used a caliper. I actually own one. You have a good point. It would be hard to know where to place the caliper to measure it.