neondeon298 Posted February 10, 2017 Share Posted February 10, 2017 Ok... so I have seen on some drawings that the draftsman will add "First Angle Projection", "Third Angle Projection", that time of thing to assist the viewer in understanding what they are looking at. I am adding a circle with 0, 90, 180, and 270 degree locations with centermark to make sure whoever is viewing knows those directions for all holes on the drawing. What is that type of thing called? A Compass, a datum.... I have no idea and can't find it in any of my books or can't google because I don't know what its called. Any ideas? Quote Link to comment Share on other sites More sharing options...
lrm Posted February 11, 2017 Share Posted February 11, 2017 I think the term you are looking for is "compass rose". For example, https://www.shutterstock.com/image-vector/brown-compass-rose-isolated-on-white-40971652 There are standard symbols to indicate whether a drawing is 3rd angle (USA and Australia) or 1st angle (ROW aka Rest of World). Google "3rd angle projection symbol". Quote Link to comment Share on other sites More sharing options...
ReMark Posted February 11, 2017 Share Posted February 11, 2017 Can we see what the drawing looks like? Quote Link to comment Share on other sites More sharing options...
neondeon298 Posted February 16, 2017 Author Share Posted February 16, 2017 I can't post company drawings. Maybe I'll draw one up and put it up here later that isn't a job drawing. Quote Link to comment Share on other sites More sharing options...
ReMark Posted February 16, 2017 Share Posted February 16, 2017 Irm's answer wasn't what you were looking for? What kind of drawings are we talking about? Quote Link to comment Share on other sites More sharing options...
neondeon298 Posted February 16, 2017 Author Share Posted February 16, 2017 I did use Irm's. I just have this funny feeling there is a more technical drafting term as a "compass rose" is used for maps and globes. Quote Link to comment Share on other sites More sharing options...
ReMark Posted February 16, 2017 Share Posted February 16, 2017 What kind of drawings are we talking about? Are you showing all the typical views one might expect to see such as top, front, side and isometric? Quote Link to comment Share on other sites More sharing options...
neondeon298 Posted February 16, 2017 Author Share Posted February 16, 2017 Its basically a 5x5x0.5" block of metal with 5 holes drilled from front face to bottom face. And due to the amount of different details on the drawing I didn't want to add 0, 90, 180, 270 to each (or one) of those holes. So bottom left corner of paper gets a compass rose. But drawing had Front Face, Side view, and other specific detail. Sorry I have to be vague. Quote Link to comment Share on other sites More sharing options...
neondeon298 Posted February 16, 2017 Author Share Posted February 16, 2017 Instead of Front Face, I should have said top face. So they are drilled straight through from Top to Bottom (the thickness of the plate). Quote Link to comment Share on other sites More sharing options...
ReMark Posted February 16, 2017 Share Posted February 16, 2017 I guess I'm just not understanding the need for the 0, 90, 180, 270 markings. Wouldn't the center of each hole be indicated by distances from the centerlines of the plate? I do tank fabrication drawings and we locate nozzles on the top, bottom (where applicable) and sides of a tank using a degree circle because when the tank is placed in the field the nozzle positions are critical for matching up with existing and new piping. Quote Link to comment Share on other sites More sharing options...
neondeon298 Posted February 16, 2017 Author Share Posted February 16, 2017 This job itself is putting the 5 holes into the plate, with centermark locations off of one corner. But inside those holes are EDM notches with super tight tolerances. The orientation of that notch on the hole side-wall is what the need for degree location was. Notch A may be at 90, another at 270, that kind of deal. And I didn't want to call them out individually for lack of space with leaders. Quote Link to comment Share on other sites More sharing options...
ReMark Posted February 16, 2017 Share Posted February 16, 2017 And now the picture becomes a little clearer. OK. Well I've seen a number of different types of drawings from different disciplines in my career but I can't recall there being a special symbol for what you are attempting to show. Are the notches only located at the quadrants of a hole? Could a notch be located at 127 degrees for example? Are the holes numbered? Is the location of the notch somehow indicated on the edge of the hole with a symbol of any kind? I'd consider numbering each hole then including a table that indicates the hole number and the location in degrees of where the notch should be located. Quote Link to comment Share on other sites More sharing options...
neondeon298 Posted February 16, 2017 Author Share Posted February 16, 2017 In this case only on quadrants. I have had others that require non-quadrant locations. That's why I felt it simpler to just keep a General notation of which way is 0°. Quote Link to comment Share on other sites More sharing options...
ReMark Posted February 16, 2017 Share Posted February 16, 2017 I like my table idea. Quote Link to comment Share on other sites More sharing options...
neondeon298 Posted February 16, 2017 Author Share Posted February 16, 2017 Quote Link to comment Share on other sites More sharing options...
rkent Posted February 16, 2017 Share Posted February 16, 2017 In this case only on quadrants. I have had others that require non-quadrant locations. That's why I felt it simpler to just keep a General notation of which way is 0°. Better include the other quadrant degrees so they know for sure that what you consider as 90 degrees is not 270 to them, etc. Quote Link to comment Share on other sites More sharing options...
neondeon298 Posted February 16, 2017 Author Share Posted February 16, 2017 I did. I put 0, 90, 180, 270 Quote Link to comment Share on other sites More sharing options...
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