The mechanical drawing below contains two dimensions (2-Ø2.30 and 4-Ø0.92) that I can't make heads or tails of. I have spent quite a while researching mechanical dimensional and tolerance conventions again, since I could not remember what this format meant. I was not able to find this particular format after looking through just over ten web pages with varying search terms.

My educated guess would be that the prefix (4- / 2-) is some special format of a tolerance value. Since the drawing is in millimeters and the hole diameters are quite small, I don't assume these prefixes to be in millimeters. From what I can tell, the suggested diameters are 2.3mm and 0.92mm, but I stand to be corrected.

I would appreciate any feedback on what these values exactly refer to.

Connector mechanical drawing

Source: https://katalog.we-online.de/em/datasheet/61400416021.pdf


1 Answer 1


Number of holes

2-Ø2.30 means two holes, each 2.3mm in diameter. It would be more usual to write this as 2xØ2.30, but given the numbers match the number of holes drawn, I'm confident it's correct.

There are several different formats for dimensional tolerances, but all the ones I know of are either 1) two separate numbers, usually one above the other, 2) placed after the dimension or 3) follow the strict rules of GD&T

  • \$\begingroup\$ That sounds reasonable. I am well aware of the standard 2xØ2.30 convention for the number of holes, but I never suspected it to be another form of just that (since the presence of +/- usually indicates tolerances). Thank you! \$\endgroup\$ Nov 23, 2018 at 10:53
  • \$\begingroup\$ @BenediktM. If that completely answers your question, you can tick the green check mark next to my answer, which will tell other users that the question has been satisfactorily answered. \$\endgroup\$
    – Jack B
    Nov 23, 2018 at 18:39
  • \$\begingroup\$ I know, but I wanted to give other people a chance to present another opinion on this, since you did not cite a reference that confirmed your thought. However, I am pretty sure that your solution is the correct one. \$\endgroup\$ Nov 23, 2018 at 22:08

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