Technical Drawing Question

Hi, if my post is in the wrong section please be so kind & let me know. Same goes to :If this kind of question is already somewhere posted.

Now, i got a technical drawing that gives me a measure "Roundness with a Maximum condition".(its a shaft detail)
My issue with this measure is that it asks a roundness w/o any deviation. Also it gives me a maximum condition so called tolerance(or bonus). Shouldn't there be a +/- tolerance for this. If my question is unclear let me know & i will try to rephrase it.

Thanks in advance!

Wes Cisco over 4 years ago

Your Mamma Magnetizes Vexactiousness

*sheesh* I have not felt this needed explaining in over a decade. Get Off My Lawn!
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Kp61dude! over 4 years ago in reply to Wes Cisco

Ah, that was my other guess.
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Villem89 over 4 years ago

I assume you also have a size dimension for the shaft? All the tolerance you have for the roundness comes from the size bonus.

Shaft itself should be Ø 14 0/-0.02. As i understand is that -0.02 should be my max for shafts roundness?

Ty for advance!
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Schrocknroll over 4 years ago

Seeing that there is no official interpretation of that callout, since it doesn't conform to the standard, your best bet is to talk to the engineer who drew it or the customer for interpretation.
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Villem89 over 4 years ago

Thank you all for helping on this matter.
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Villem89 over 4 years ago

Another matter where i would like a clarification(do i understood it correctly) is about positioning. Drawing states Datums A B C
datum C is For the hole 1.5mm
A is the plane
B is the details outer diameter which is say 35 mm.
Position is asked for a hole diam. 0.9mm

Now, i understand that A is primary datum (From which others must be positioned to 0.1 max). Usually there is a cap between B and C, so B would be secondary and C would be then tertiary datum. Right now i understand that B & C are sharing secondary datum or does it even matter how they are asked?

PS: if my question or a statement is false is confusing please let me know.
Same goes to this post(i thought i would just all my questions from 1 post)

*There are no wrong questions, only wrong answers*

Ty for advance!
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mtalla over 4 years ago

Roundness can only be a positive number.
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