Can someone explain how to interpret these metric tolernaces. I know the diameter symbol and number, but how should I read the
It should be read as a just like a +/-, it's a tolerance as in 2mm (-0.007 to -0.011)
Could also be read as 1.993-1.989mm.
I want to read these as bilateral tollerances, but the drawing does look a little strange to me as they are using "comas" instead of decimals and also what appears to be a double negative bilateral tolerance. In any case, I would be inclined to interpret these dimensions as a diameter of 22mm +0 / -.08 , 7mm +0 / -.022 , and 2mm -.007 / -.011.
So for example, the last one would translate to values of (1.993mm to 1.989mm.)
This would be my best guess - to treat them like bilateral tolerances with the comma being a decimal.
I would read them as bilateral tolerances as well.
I think the comma is there instead of a decimal point because this is an ISO standard drawing prepared for europe (watch out for first -angle projection in the views)
The doubly-negative bilaterial tolerance on the right-most dimension probably indicates an interference fit for the nominal condition. That's a convention that varies from one manufacturer to another and usually for the convenience of listing the dimension as being a nominal stock size.. I personally, would just write it as 1,993 +0/-0,004 and let the machinist figure out the stock.
Good insight - thanks
Great! Thanks for the help, insight, and timely responses.
Please note that Ø7 is a datum.
You are right about them listing the dimension for the sake of having a nice "nominal" number. This looks like a drawing of a motor from a catalog, and so I am pretty sure this is more for the convenience of the customer rather than a machinist. The different sized motors would have different shaft sizes, this would be the "2 mm" shaft. But then it is undersized probably so that it would slip fit through a bearing or something. I don't encounter it that often but I think it is fairly common in metric drawings to use the double negative bilateral tolerance (or double positive even). A lot of the shaft fits are like that like g6, f6 etc. and for holes G6, F6 etc.
Retrieving data ...