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Tolerence measurement +0.02 to + 0.05

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  1. Mar 11, 2015 #1
    Hi,

    I am new here. I would like to know if anyone can explain to me the meaning of +0.02 to +0.05 in a fabrication drawing.Does this part needs to be fabricated in this range of tolerence or,i should follow the maximum value.

    Appreciate your replies.

    Thanks.
     
  2. jcsd
  3. Mar 11, 2015 #2
    There should be a nominal value associated with the tolerance. That's the value you should try to hit, but the tolerance just gives the acceptable range for inspection not to reject the part.
     
  4. Mar 11, 2015 #3

    Bandit127

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    Gold Member

    You should aim for the middle of the tolerance, or size +0.035. That then gives you a tolerance of ±0.015.

    So if the nominal is 10.00, aim for 10.035 and that comes with a tolerance of ±0.015.

    Shaft and hole diameters are commonly specified like this. Specifying (e.g) 10.00 as the nominal maintains the design intent, while the shaft will normally a be negative tolerance and the hole a positive one, and that makes it work in the real world.
     
    Last edited: Mar 11, 2015
  5. Mar 12, 2015 #4
    Tolerances can be used to ensure parts mate correctly.

    For example, if you have a machined bore hole which is designed to accept a shaft through it, you could put a tolerance on both items. The Bore hole say 100mm diameter, you could put a tolerance on of your +0.02 +0.05.
    For the shaft, you could say 100mm diameter - 0.02 -0.05. What this is doing is to ensure that the shaft will fit in the bore. If you had no tolerance, the bore & the shaft could have an identical diameter, and wouldn't fit.
     
  6. Mar 12, 2015 #5
    Yeah, I think I gave some bad advice there. I don't deal much with double plus tolerances like that, so I guess I would make try to build it to the middle of the tolerance zone.
     
  7. Mar 12, 2015 #6

    Baluncore

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    Science Advisor

    A "press fit" requires the shaft be specified oversize compared with the nominal bore size.
    A non-interference or a lubricated fit, requires the bore be specified oversize compared with the nominal shaft size.
     
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