Please help me to identify what C5 stands for in this picture. Full drawing is available here.


  • $\begingroup$ This Wikipedia article gives a hint it might be centre-to-centre distance of two features, but I cannot corelate. $\endgroup$ Dec 19, 2020 at 21:03
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    $\begingroup$ That's a 5mm champher! $\endgroup$ Dec 19, 2020 at 21:08
  • $\begingroup$ Defined in a similar way to the 4mm radius labeled R4.0 $\endgroup$ Dec 19, 2020 at 21:09
  • $\begingroup$ @JonathanRSwift Thanks! Just to confirm - top line length then equals to 28 - 5 - 5 = 18? $\endgroup$ Dec 19, 2020 at 21:13
  • $\begingroup$ Yep, and the angle will be 45degrees. $\endgroup$ Dec 19, 2020 at 21:16

1 Answer 1


The "C5" annotation in this example refers to a "5mm Champher". It's important to note, however, that this is non-standard notation. I have included an example below with the standard annotation for the champher on the LHS, and another alternative on the RHS. 5mm champhers


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