Machinist gage set question

[Dirty Dan Dawkins]

What are the M0,M1, M2, M3, P1, P2 etc designations for gages?

What does the - and + mean?

 

[Crooked River Pete, SASS 43485]

What kind of gages are you talking about? Blocks? Pins? Thread? " -" usually means no bigger than nominal size while "+" means no smaller. "M" might be for metric gages, 1,2,3, can refer to the size of the set, a 1M set contains 47 metric blocks, a 2M set contains 88 metric blocks. Information from my machinist handbook 

[Subdeacon Joe]

With gauge pin sets the M# is a range.  M0 sets run .011" to .060".  M1 is .051" to .250". M2 is .251" to .500".  M3 is .501" to .750".

 

Minus gauge pins, in general are 0.0002" under the nominal size, plus gauge pins will be 0.0002" over nominal.

 

Say you have a hole that is called out on the drawing as 0.197" +/- 0.002".  You make up your GO/NOGO pin set with a 0.195"+ pin and a 0.199- pin.  The ensures that you are not under the minimum or over the maximum.

[Subdeacon Joe]

https://www.newmantools.com/meyer/pluggage_ABC.htm

[Dirty Dan Dawkins]

15 hours ago, Subdeacon Joe said:

With gauge pin sets the M# is a range.  M0 sets run .011" to .060".  M1 is .051" to .250". M2 is .251" to .500".  M3 is .501" to .750".

 

Minus gauge pins, in general are 0.0002" under the nominal size, plus gauge pins will be 0.0002" over nominal.

 

Say you have a hole that is called out on the drawing as 0.197" +/- 0.002".  You make up your GO/NOGO pin set with a 0.195"+ pin and a 0.199- pin.  The ensures that you are not under the minimum or over the maximum.

Thanks that explains a lot.