i just like to ask what is the smallest garduation for dial test indicator/peak test meter?
I was asked to look for a 0.0001 mm or 0.1 um graduation and sad to say i dont see anything like this.
kindly help me

The best resolution mechanical dial indicator I know about is the Mahr 1002 Supramess. However, it reads 0.0005 mm, not 0.0001 mm. Mahr does make a digital indicator with a resolution of 0.0002 mm, the Extramess 2000.

In my experience, for sub micron indication, one uses an inductive measuring probe (aka "Gage Head"), often good for 0.000 02 mm or better, and a gaging amplifier. See the Federal 832 and compatible gage heads.

I have no affiliation with Mahr or Federal other than satisfied customer.

I know that CE Johansson makes (or made) a 0.25 µm indicator. To go any tighter than that would require the use of a precision glass scale and reader device. Heidenhain is probably your best bet there, or possibly Mahr. The big question is not whether you can get a device with the accuracy and resolution of 0.1 µm, it is whether you can make a reliable measurement at that level.

Examples:

20°C ± 0.25°C will give you a swing of over 1 division on a 25mm part if it is made of steel.

The deformation caused by the contact point will be measurable.

Who would calibrate the gage? Very few labs can boast ±0.025 µm uncertainty on their calibration standards.

Some food for thought.

Ryan