Tolarance for machining
Tolarance for machining
(OP)
Dear All,
A simple question but always I ger confusion with this.
If I given a tolarance on shaft Dia. 10 -0.030 & hole Dia. 10 +0.050/+0.030 then the machinist will make the job at higer tolerence of hole and lesser of shaft?
Yash
A simple question but always I ger confusion with this.
If I given a tolarance on shaft Dia. 10 -0.030 & hole Dia. 10 +0.050/+0.030 then the machinist will make the job at higer tolerence of hole and lesser of shaft?
Yash





RE: Tolarance for machining
RE: Tolarance for machining
The part is acceptable anywhere within the tolerance range.
As such, machinists typically aim for somewhere in the middle of the tolerance range to allow for manufacturing capability tolerance.
So, your shafts will probably tend to be around 9.985 & your holes around 10.015.
This will vary slightly depending on manufacturing process. For instance if there is a standard tool size toward one limit, they may use that standard tool.
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: Tolarance for machining
On a one-off job, a machinist's pride is at stake. If the tolerances are fairly loose, a lot of them will make the features as close to maximum material condition as possible.
RE: Tolarance for machining
However, I guess my point is you shouldn't rely on it when specking the tolerances. You should specify the tolerances required by function - as ornerynorsk mentions - so that any part in those tolerances is good.
If the Op really wants the shaft nearer 10 then he should specify 10-.001 or something, and accept the consequences.
I realize it's not quite this black and white sometimes but trying to rely on general trends rather than explicit requirements can be risky.
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: Tolarance for machining
RE: Tolarance for machining
I hope not
RE: Tolarance for machining
However, I wouldn't assume any of this for designing the tolerancing to a part even if I knew everything possible about how the part is to be machined. Assume the part will come in at the worst extremes of tolerance - because those conditions still have to work.