chloe2012 Posted March 31, 2012 Share Posted March 31, 2012 (edited) Hi, I think I followed the text correctly to find the true lengths. It's what to do next that I am stuck at. I think I have what you said correct now. Thank you so much for helping me and everyone on these forums out especially on a Saturday. Edited March 31, 2012 by chloe2012 Quote Link to comment Share on other sites More sharing options...
JD Mather Posted March 31, 2012 Share Posted March 31, 2012 Oops, I just noticed that the circle is offset from center so B-10' is not equal to A-10' Your circles don't look like perfect radius. Don't type in the radius - use snap points. Your next step will be to determine the length of arc from 10-9. Not the cord length (many books miss this) you need the arc length. Once you find this it is the same for all (9-8 is the same as 10-9). Tip- you can find the arc length by copy and paste pie shape away from the drawing. trim the pie list the arc Draw circle of R 10-9 arc length at point 10' in your flat development.. Draw circle of R A-9' at point A Where these two circle intersect is point 9' you now have line A-9 Quote Link to comment Share on other sites More sharing options...
chloe2012 Posted March 31, 2012 Share Posted March 31, 2012 No, its not centered. Do I have this first stage correct? Quote Link to comment Share on other sites More sharing options...
chloe2012 Posted March 31, 2012 Share Posted March 31, 2012 (edited) Ok, I have done that step, hopefully correct Project 7 - PLATE 3.dwg Edited March 31, 2012 by chloe2012 Quote Link to comment Share on other sites More sharing options...
ReMark Posted March 31, 2012 Share Posted March 31, 2012 I'm not at my CAD computer thus the reason for my question. Are you working on the Penn-Foster HVAC project? Quote Link to comment Share on other sites More sharing options...
chloe2012 Posted March 31, 2012 Share Posted March 31, 2012 Yes I am. I have seen the pictures of Plate 3 posted. It shows that the end result is supposed to be but not how to get there. I attached a picture of where I have reached. I assume I do the same thing on the left side but not sure what to do next on the right. Quote Link to comment Share on other sites More sharing options...
chloe2012 Posted March 31, 2012 Share Posted March 31, 2012 This is what I have come up with following instructions that I found online, though they were for a symmetrical piece. I know something is wrong as my arc on the inside isn't correctly meeting the lines for each point. However, I do not know what. Please help when able. Project 7 - PLATE 3.dwg Quote Link to comment Share on other sites More sharing options...
JD Mather Posted April 1, 2012 Share Posted April 1, 2012 It should be a spline curve - not an arc. But you have point D in the wrong location. Draw circle R A-D at A. Draw circle R A-7 with center at 7 (A-7 and 7-D are same length). Where these two circles intersect is the actual location of point D. Quote Link to comment Share on other sites More sharing options...
chloe2012 Posted April 1, 2012 Share Posted April 1, 2012 HI, Think I have it all correct now...hopefully Project 7 - PLATE 3.dwg Quote Link to comment Share on other sites More sharing options...
bego Posted April 28, 2014 Share Posted April 28, 2014 hello, please i need hel for DRAFTING THE 14X16X6 HVAC patterns. thank you! Quote Link to comment Share on other sites More sharing options...
ReMark Posted April 28, 2014 Share Posted April 28, 2014 Just what is it that you need help with specifically? Did you look at some of the similar HVAC threads to this one? A number of images are available. Quote Link to comment Share on other sites More sharing options...
J-stone Posted June 30, 2014 Share Posted June 30, 2014 Hello, after reading through this thread, and others, I still do not know how to find the "true lengths". Once I understand something, then I know it forever, unfortunately I just don't get it. Please someone, spell it out in simple terms. Keep in mind I am an ex-framer, so not too bright Quote Link to comment Share on other sites More sharing options...
ReMark Posted June 30, 2014 Share Posted June 30, 2014 J-stone: Which HVAC project are you doing? The regular one or the elective? True lengths are needed when a side is slanted. For an example of what I am talking about see this... http://www.achrnews.com/articles/laying-out-rectangular-duct-transitions Quote Link to comment Share on other sites More sharing options...
J-stone Posted June 30, 2014 Share Posted June 30, 2014 It's the regular one, project 7 HVAC. Quote Link to comment Share on other sites More sharing options...
J-stone Posted June 30, 2014 Share Posted June 30, 2014 I guess my question is; how do I project the true length lines, how do I figure out what the radius is to project the lines out and down from my top view to my front view? Quote Link to comment Share on other sites More sharing options...
J-stone Posted June 30, 2014 Share Posted June 30, 2014 So how does one go about finding what the true length's are? Quote Link to comment Share on other sites More sharing options...
ReMark Posted June 30, 2014 Share Posted June 30, 2014 I have not worked on the HVAC project personally but I have posted images from it that were handed over to me by a former Penn-Foster student. Have you looked at any of the other threads regarding this project as I know there are at least two that have images of some if not all of the plates. See this thread...http://www.cadtutor.net/forum/showthread.php?59190-HVAC-School-project I have copies of the drawings done by Car5858 that he included as images in the thread. Are you working on Plate 3? Quote Link to comment Share on other sites More sharing options...
J-stone Posted June 30, 2014 Share Posted June 30, 2014 Ya I've read through all the threads that have HVAC anywhere mentioned in conversation. Here is a screenshot. I just need to know the process that one does to figure out the projection lines to find the true length's. Without just looking or copying, I am trying to figure out how to figure out what the true length's are. If that makes sense. On a side not, I am obviously almost done with this program, but I do have a 98% average. I got dinged on two drawings for following the directions to the letter. So, for the last few drawings, I am utilizing this wealth of knowledge that you guys have. I would preffer to not have my grade drop anymore than it already has. But, honestly, I am tempted to just blow through it and leave this horribly compiled course behind. On a side note, would anyone reading this know of a GOOD course for structural drafting? Quote Link to comment Share on other sites More sharing options...
ReMark Posted June 30, 2014 Share Posted June 30, 2014 I am not well versed in HVAC re: sheetmetal fabrication so I would have to defer to forum members JD Mather and/or Tanner Frampton when it comes to advising you on the proper procedure. Quote Link to comment Share on other sites More sharing options...
ReMark Posted June 30, 2014 Share Posted June 30, 2014 I guess my question is; how do I project the true length lines, how do I figure out what the radius is to project the lines out and down from my top view to my front view? After looking at Car5858's drawing (in the thread I provided the link to) I think I know how the arcs are created. Draw circles using corner 'B' as the center through points 10, 11, 12 and 1 of the cylinder; trim as required. Like this... If I am wrong JDM will be sure to castigate me and Tanner Frampton will most likely want to castrate me. Either way, you'll get a more definitive answer. Quote Link to comment Share on other sites More sharing options...
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