Limits and fits

[xf8u39]

Hi, what is the correct way to dimension upper and lower limits for holes on a drawing. Should the MMC be above LMC? OR the higher value be above the lower.I prefer the latter to avoid confusion but I have been told that the former is the correct way.Please advise

 

[Belanger]

The higher number above the lower number; doesn't matter whether it's a hole or a pin.

John-Paul Belanger
Certified Sr. GD&T Professional
Geometric Learning Systems

 

[dgallup]

Depends on which drawing standard you use. I worked for a company once that put the first value a machinist would approach on top. So if he was drilling a hole, the lower value went on top. That's definitely old school these days and that company no longer exists (I don't think that's the reason but using proprietary standards didn't help).

The point is, no one can tell you what is right or wrong until you tell use what standard you are using.

 

[SeasonLee]

Per Y14.5M-1994 Sec 2.2 page 24
The high limit (maximum value) is placed above the low limit (minimum value). When expressed in a single line, the low limit precedes the high limit and a dash separates the two values.

You may also find it on Y14.5-2009 Sec. 2.2 at page 24 as well.

SeasonLee

 

[xf8u39]

Great thanks guys.