Use of OD Indicator Micrometers - Round Feature vs. Flat Surfaces

Q

QC Rick

I have recently heard of this technique of setting up an indicator Micrometer (OD) that if your are going to measure a round feature you set up the tool with a round gage (Deltronic gage pin) and conversely, if you are going to measure flat surfaces you use gage blocks!?
(Note this goes for any OD micrometer.)

Personally I have never heard of this and have not been taught this technique in any class (24 years). :notme:

Comments and or direct information is very much welcome! ;)
 

Jim Wynne

Leader
Admin
I have recently heard of this technique of setting up an indicator Micrometer (OD) that if your are going to measure a round feature you set up the tool with a round gage (Deltronic gage pin) and conversely, if you are going to measure flat surfaces you use gage blocks!?
(Note this goes for any OD micrometer.)

Personally I have never heard of this and have not been taught this technique in any class (24 years). :notme:

Comments and or direct information is very much welcome! ;)

I haven't used an indicating mic in a while, but when I did I usually set it with whatever was convenient--blocks or a pin. I don't think they're generally of much use except for sorting. You can do a simple experiment for yourself--just set it with a pin and measure a block of the same size. I doubt that you'll see any difference.
 
T

True Position

I would guess a potential difference would be wear on the anvil faces, something used to gage round parts would more likely have uneven ( shaped wear compared to something used to measure flat faces. I suspect it doesn't make a difference in 99%+ of cases.
 
J

justncredible

Hawat is close.

You can check the paraellism of the mic advils with a gage ball. Since only the highest spots are hitting at a single time. It works and is a valid way to prove a mic is out of paraelle.

Is it good for setting up to check parts, no not really since you might set to a pit or other surface error on the advils. In the use of a mic you will use feel or in the case of a indicator mic a spring, in both cases you will be moving the part on the advils and looking for the reading. Setting to a gage pin could increase the error of the reading, a risk in any measurement.

So either can be used and are, someone was bs'ing you.
 
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