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