[An...] Posted June 24, 2020 Share Posted June 24, 2020 Hi everybody, i have to measure characteristics attached. How can I measure Datum C and D? 3d line between cones feature? 3d line between circle on cone features? I would like to know if anyone has already tried. Please admit that the two cone surfaces are grinded and has perfect shape. Thanks in advance Link to comment Share on other sites More sharing options...
[Me...] Posted June 24, 2020 Share Posted June 24, 2020 Since it is a small area, you may want to use "Circle on a cone" and draw your 3d line between the two. Link to comment Share on other sites More sharing options...
[SH...] Posted June 24, 2020 Share Posted June 24, 2020 Please sign in to view this quote. I would go circle on cone and create a 3D line. Your datum did not satisfy the conditions of the datum requirement, these cones are going to be functional in the assembly,I don't think... Link to comment Share on other sites More sharing options...
[Cl...] Posted June 24, 2020 Share Posted June 24, 2020 Measure the two cones and construct a 3d line. The runout in the top view calls it out a composite datum (C-D), but the one below has no dash between? Link to comment Share on other sites More sharing options...
[To...] Posted June 24, 2020 Share Posted June 24, 2020 I would measure the cone, and then the flat plane surrounding the cone, and intersect the two. Repeat on other end. Then I construct a 3d-line between the two intersection points. Link to comment Share on other sites More sharing options...
[Jo...] Posted June 24, 2020 Share Posted June 24, 2020 Please sign in to view this quote. This method will get a stable vector. If you measure the cone only , it will have projected error. If you measure a circle on a cone, it is ALIGNMENT dependent, which potentially could be an ellipse in form. Link to comment Share on other sites More sharing options...
[Ke...] Posted June 24, 2020 Share Posted June 24, 2020 I would measure the two cones, and construct a 3D line. I would also report the form of each cone for reference; If there is an issue with parts passing spec, this may provide a clue. IMO, some of the other options may gloss over imperfections of the datums. Link to comment Share on other sites More sharing options...
[Ia...] Posted June 24, 2020 Share Posted June 24, 2020 Please sign in to view this quote. You would have to evaluate those cones as Outer Tangential right? Link to comment Share on other sites More sharing options...
[An...] Posted June 24, 2020 Author Share Posted June 24, 2020 Please sign in to view this quote. The datums runout are the same for both. The second image is a write mistake. Link to comment Share on other sites More sharing options...
[Ri...] Posted June 24, 2020 Share Posted June 24, 2020 This looks like a typical input/output shaft drawing. They tend to draw it this way because majority of people would just put this on a bench-center between centers, and capture the runouts. In the CMM world, this becomes difficult. Link to comment Share on other sites More sharing options...
[Er...] Posted June 24, 2020 Share Posted June 24, 2020 Please sign in to view this quote. Richard, This is exactly what we do. A part like this for the runout we check on centers, rather than using a CMM. We setup up however many .0001" indicators on the part and check them all at once. It's much faster. Link to comment Share on other sites More sharing options...
[Ri...] Posted June 24, 2020 Share Posted June 24, 2020 Please sign in to view this quote. Yeah. I got fast tracked into the shaft measurement world. CMMs work great if they give you normal datums, but in this case it can be a pain in the butt. I've seen some machines that get this option. Link to comment Share on other sites More sharing options...
[Da...] Posted June 24, 2020 Share Posted June 24, 2020 It's impossible to check the runout of that I.D. to centers without a CMM. The centers are for construction, chances are they are un-used in the final use of the part. Not a great way to design a part. We would get parts like this, but the runout would be called out to a critical O.D. Link to comment Share on other sites More sharing options...
[Ke...] Posted June 24, 2020 Share Posted June 24, 2020 Please sign in to view this quote. Correct Link to comment Share on other sites More sharing options...
[Ri...] Posted June 24, 2020 Share Posted June 24, 2020 Please sign in to view this quote. I agree. It's just typical. I see large gears dimensioned this way as well. Link to comment Share on other sites More sharing options...
[Da...] Posted June 25, 2020 Share Posted June 25, 2020 Please sign in to view this quote. Yes ! They are meant for centers. Link to comment Share on other sites More sharing options...
[An...] Posted June 26, 2020 Author Share Posted June 26, 2020 Thank you guys. I know isn't a best way to check those runout but in my workshop is only one. I take some good posts and i will perform R&R in order to define the limit. keep in touch! Link to comment Share on other sites More sharing options...
[An...] Posted October 28, 2020 Author Share Posted October 28, 2020 Hi everybody, i just want to update this topic. I made a lot of R&R measurements about it and i explain to all which construction i use to fix the runout meas. I measured datum C and D like a cone with 3 circle path for each (GG evaluation). I created a 3d line through all 6 circles centers, then I used it like runout datum. I know that isn't the purpose of the drawing but it give me a good comparison (gap max 0.006mm) with customer measurement. This construction made it possible to continue with the project. Obviously, when you have a similar tolerances the only way is use bench-center measurements like Eric Crawford's suggestion.2020-10-28 13_46_21-Window.png Link to comment Share on other sites More sharing options...
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