How do I find the location of the corners in this print? (Novice Post)
Close
Login to Your Account
Page 1 of 2 12 LastLast
Results 1 to 20 of 24
  1. #1
    Join Date
    Dec 2017
    Country
    UNITED STATES
    State/Province
    Illinois
    Posts
    5
    Post Thanks / Like
    Likes (Given)
    8
    Likes (Received)
    0

    Default How do I find the location of the corners in this print? (Novice Post)

    I am getting back into CNC Programming and trying to hone my skills by programming one of the more difficult parts I could find. I am having trouble finding the coordinates for some of the angles and circular cuts, but I can seem to figure out how to find them using trig or by looking at the print. What should I do?

    Imgur: The magic of the Internet
    Here is a link to a picture of the print. I circled the corners I am talking about.

  2. #2
    Join Date
    Aug 2004
    Country
    UNITED STATES
    State/Province
    Virginia
    Posts
    2,698
    Post Thanks / Like
    Likes (Given)
    205
    Likes (Received)
    1161

    Default

    Although there are many here that use CAD/CAM, you might get more results on the CAD/CAM forum.

  3. #3
    Join Date
    Apr 2018
    Country
    UNITED STATES MINOR OUTLYING ISLANDS
    Posts
    6,749
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    3234

    Default

    Quote Originally Posted by bob1352 View Post
    There's nothing there. I turned off all my filters and everything, still no go.

    Just put it here.

    And if I caught something, I'm gonna go get covid and cough on you !

  4. #4
    Join Date
    Sep 2002
    Location
    People's Republic
    Posts
    5,639
    Post Thanks / Like
    Likes (Given)
    671
    Likes (Received)
    3508

    Default

    Looks like a programming example part

    Appears the corner in Y is defined, X might be off the page at the top

  5. #5
    Join Date
    Aug 2010
    Location
    Minnesota USA
    Posts
    295
    Post Thanks / Like
    Likes (Given)
    1
    Likes (Received)
    56

    Default

    From the progression of reference point numbers, the X0/Y0 is in the upper right corner of the part.

  6. #6
    Join Date
    Feb 2005
    Location
    Hatch, NM Chile capital of the WORLD
    Posts
    9,508
    Post Thanks / Like
    Likes (Given)
    15877
    Likes (Received)
    11513

    Default

    All the info you need is there, it can be trigged out, but some of its going
    to be tricky, like where you have an angle intersecting an arc.

    It actually looks like more of a fun geometry/trig problem than a programming problem.

    The way we cheat in the machining world, is we just draw it up and let the CAD do
    all the work. That shouldn't take but a few minutes and you'll have everything
    you need.

  7. Likes Mtndew, AARONT liked this post
  8. #7
    Join Date
    Nov 2003
    Country
    UNITED STATES
    State/Province
    Texas
    Posts
    5,702
    Post Thanks / Like
    Likes (Given)
    202
    Likes (Received)
    1945

    Default

    I have never seen a drawing like that before and I wonder just where it came from. My first guess would be a high school drafting class. But there is a NIMS logo on the sheet. I do not like the use of two entirely different ways of showing dimensions. I also do not like the fact that there is nothing to indicate the units of those measurements. I would assume metric, but even then are the numbers mm, cm, m, or km? Perhaps microns?

    As far as I can tell and assuming the numbers in the rectangles are dimensions, all the features are located just fine with respect to each other. And the one angle that is on the drawing appears to be referenced to a vertical line.

    BUT absolutely none of those features are located with respect to the edges of the part. Nor is there any indication of any point that would be at the center of the overall rectangle. Perhaps that location is of no importance and the overall pattern can be anywhere on the part. Even the sole angle shown is not referenced to an edge. Perhaps the overall pattern can be rotated within any range as long as the overall pattern still fits inside the overall rectangle of the part? Perhaps the designer just assumed that the overall pattern would be centered on the part and some of the lines would be parallel to the edges. But that is just speculation. I consider it to be a great example of how not to draw anything.

    The full sheet is not shown so I ask if there is any other information on the sheet that you are not showing? Perhaps in a note?

    Another thing is the corners where two straight paths or a straight and a curved path meet are drawn with sharp corners. That is going to be difficult to make without hand work.

  9. #8
    Join Date
    Oct 2005
    Country
    UNITED STATES
    State/Province
    Pennsylvania
    Posts
    20,194
    Post Thanks / Like

    Default

    Are you not cheating by asking here ?

  10. #9
    Join Date
    Nov 2018
    Country
    UNITED STATES
    State/Province
    Michigan
    Posts
    656
    Post Thanks / Like
    Likes (Given)
    338
    Likes (Received)
    395

    Default

    Better question is, do you need to? The corners in question are mostly where arcs intersect with lines, so they are fully defined by the center location and radius. Can they not be defined that way for whatever you are stuck on? Is it programming you need help with, or metrology to validate a success?

  11. #10
    Join Date
    Jun 2012
    Location
    Michigan
    Posts
    5,569
    Post Thanks / Like
    Likes (Given)
    5251
    Likes (Received)
    3547

    Default

    Quote Originally Posted by bob1352 View Post
    but I can seem to figure out how to find them using trig or by looking at the print. What should I do?
    Brush up on your trig. All of the information you need is on that drawing.

  12. Likes LockNut liked this post
  13. #11
    Join Date
    Sep 2017
    Country
    UNITED STATES
    State/Province
    South Carolina
    Posts
    746
    Post Thanks / Like
    Likes (Given)
    594
    Likes (Received)
    606

    Default

    What i see is 2.5 x 4 rectangular part with all the features cut down as step. Hence all the chamfers cut on the raised up profile. I tried to draw it up in cad, but couldn't get the numbers to add up. There is something going on that is not obvious to me.

  14. #12
    Join Date
    Jan 2007
    Location
    Flushing/Flint, Michigan
    Posts
    9,724
    Post Thanks / Like
    Likes (Given)
    536
    Likes (Received)
    8037

    Default

    Quote Originally Posted by Mtndew View Post
    Brush up on your trig. All of the information you need is on that drawing.
    Yes it is but I'd much rather just draw it in the CAD and ask it.
    When there were only pencil drawing boards it was done the harder way. How much trig on paper is needed to find all these points?
    Do you use a sundial to tell time or a sliderule to help trig this out nowadays?
    There is the good ole fun side of no CAD and no calculator to solve it but not very time efficient.
    Some would say CAD cheating, is a TI-35 also cheating?
    Bob
    (I did not try to draw it and there are impossible part drawings)

  15. Likes Hardplates liked this post
  16. #13
    Join Date
    Nov 2003
    Country
    UNITED STATES
    State/Province
    Texas
    Posts
    5,702
    Post Thanks / Like
    Likes (Given)
    202
    Likes (Received)
    1945

    Default

    I looked at the photo of PART of the drawing again. I do see a 7 in the second from the top place in the stack of Y numbers on the right. I guess that 7 is referring to the top edge of the part.

    However, I still do not see anything on this IMAGE of the drawing to indicate the X location of anything inside the outer edges.

    If any of you guys who keep saying that all that is needed is on this image can actually tell the X location of anything, please say so.

  17. #14
    Join Date
    Feb 2005
    Location
    Hatch, NM Chile capital of the WORLD
    Posts
    9,508
    Post Thanks / Like
    Likes (Given)
    15877
    Likes (Received)
    11513

    Default

    Quote Originally Posted by EPAIII View Post

    If any of you guys who keep saying that all that is needed is on this image can actually tell the X location of anything, please say so.
    I thunked we were just crunching the geometry for the profile. There is the bottom of a box
    on the -E- datum, I'm assuming its there. I also don't agree with the assignment of B and C and
    D and E. D,E should be B,C and vise versa. But that has nothing to do with figuring out the profile.

  18. #15
    Join Date
    May 2019
    Country
    UNITED STATES
    State/Province
    Pennsylvania
    Posts
    1,651
    Post Thanks / Like
    Likes (Given)
    830
    Likes (Received)
    1009

    Default

    I think a clarification from the customer is in order......oh wait there is no customer.....

  19. #16
    Join Date
    Feb 2010
    Location
    ch
    Posts
    2,929
    Post Thanks / Like
    Likes (Given)
    245
    Likes (Received)
    398

  20. #17
    Join Date
    Nov 2003
    Country
    UNITED STATES
    State/Province
    Texas
    Posts
    5,702
    Post Thanks / Like
    Likes (Given)
    202
    Likes (Received)
    1945

    Default

    I have easily found the X in that internet puzzle using CAD.

    IIRC, it is 8+ inches. However, I have not found any shortcut that makes doing that calculation without CAD possible. I look at it from time to time but I have not looked at the video for the answer.

    OK, making the assumption that the missing X dimension really is on the drawing, just out of the part that was posted, and looking at the geometry of the pattern I started to draw the pattern with my CAD. I started at what is the 0,0 coordinate at the upper right and drew the (90°?) arc that is closest to that starting point. Then I wanted to draw the horizontal line from the arc's upper-left corner. But I only have that starting point. There is no way to locate the end point of that line. It meets another arc with a 27 (mm?) radius but the two are not drawn as tangent and the center of that 27 mm arc is not shown in any obvious way. The radius line simply terminates at the outline of the part. It is difficult to see if there is a center indicated at that edge, but even if there is, you still need the missing X dimension to that part edge and it is NOT shown on the part of the drawing that is in the image the OP provided.

    So, I repeat my statement that "If any of you guys who keep saying that all that is needed is on this image can actually tell the X location of anything, please say so." ALL the information that is needed to just work out the pattern is NOT shown in the photo posted. I need that missing X number to draw just the second element of the pattern. Who knows what else may be missing. So, my CAD drawing of the pattern had to stop after just ONE element.

    I think the OP did not spend much time looking at the drawing because if he had, he would have realized that the missing X number is of vital importance. So he did not ensure that it was in the photo of the drawing.

    Another problem exists at the right end of the arc at the bottom which is apparently centered at -45, -80. Again, the photo cuts off a vital piece of information, it's radius. And, even with that radius, the right end of that arc is not well located. One could assume that it is at the same, -50 Y coordinate as it's left end is, but that would only be an assumption. A 74.482 mm(?) dimension at a -35° angle is shown and I guess, with some trigonometry, the X-Y coordinates of that point could be found. This is really a poor way to dimension this.



    Quote Originally Posted by dian View Post

  21. #18
    Join Date
    Nov 2003
    Country
    UNITED STATES
    State/Province
    Texas
    Posts
    5,702
    Post Thanks / Like
    Likes (Given)
    202
    Likes (Received)
    1945

    Default

    If someone handed that drawing to me and wanted me to make the part, either by manual of CNC methods, I would ball it up and throw it back while shouting as loud as I could that they should take some lessons in mechanical drafting.

    That shouting would include some carefully chosen words of the four letter variety.

    If I was forced to make it, I would make it plain that I was going to bill at my highest rate for every hour or fraction thereof used to interpret the drawing and that I would not be the least bit responsible for any errors anywhere in the process.

  22. #19
    Join Date
    Jan 2007
    Location
    Flushing/Flint, Michigan
    Posts
    9,724
    Post Thanks / Like
    Likes (Given)
    536
    Likes (Received)
    8037

    Default

    Quote Originally Posted by EPAIII View Post
    ..... This is really a poor way to dimension this.
    If you think this bad you should try making form tools for screw machines.
    The fact that the end of the leader for rad size on the bottom cut off in the picture is for sure a problem.
    The rest of it not so bad.
    We will often dimension complex form wheels in a similar ordinate fashion.
    Places like Cranden have no problem, some others come back crying and want dimensions double specified which is never good sign.
    While doable It would be quite the challenge to trig it out by hand using paper and pencil with the non-tangent rads. A whole lot of triangles.
    I do agree that it is messy.
    Bob

  23. #20
    Join Date
    Sep 2017
    Country
    UNITED STATES
    State/Province
    South Carolina
    Posts
    746
    Post Thanks / Like
    Likes (Given)
    594
    Likes (Received)
    606

    Default

    Quote Originally Posted by EPAIII View Post
    So, my CAD drawing of the pattern had to stop after just ONE element.
    I had the same problem.After I drew the 63.5MM x 101.6MM I started to run into problems with the numbers.
    So it was one and done for me also.


Tags for this Thread

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •