Measuring tolerance of +/- 0.0003"

[wangsanegara]

Hi All,

I am a new member and having difficulties in measuring a cross drilled hole in a shaft. The requirement is to measure a hole with a +/- 0.0003", nominal dia on 0.1883 Any suggestion of how to measure this other than investing in a Air gauging equipment?

Thanks

[Kelly_Bramble]

I'm not aware of any alternative technology that has the resolution you need.

How many measurements do you need to make? Can you send the part out to a capable shop?

[wangsanegara]

Hi Kelly,

Its for First Article, means that we will make about 10 parts. The problem with Air gauging method is that you will need a special Air Plug which has a nominal diameter for a specified hole. I doubt any shop will have the same exact dimension as required.

Thanks.

[Timelord]

Gauge pins can be used as go/no-go gauges. Even if you have a custom go/no-go gauge made, it is cheaper than air gauging.

Timelord

[Belanger]

But with a go/no-go method, wouldn't that physical gage also need tolerance of its own? Using the 10% rule, that means this gage would have a total tolerance of .00006, which might be another problem in itself.

[mhk665]

First i m confused because the way you have mentioned sizes is kind of non-std (0 before decimal). are these limits in inch or mm?
.1883" = 4.78 mm i think TRI-O-BORE can be used to measure such size or if u have access to advanced tools like Mic-Trac, having accuracy below 1 micron

[Kelly_Bramble]

First i m confused because the way you have mentioned sizes is kind of non-std (0 before decimal). are these limits in inch or mm?
.1883" = 4.78 mm i think TRI-O-BORE can be used to measure such size or if u have access to advanced tools like Mic-Trac, having accuracy below 1 micron

Yes, SI (Metric) units are normally illustrated with a leading zero before the decimal and Imperial units (inch) are illustrated without a leading zero before the decimal.

However, notice that the number was given with a " following.

" = inch units