How do you measure Inside diameter

Well, I still remember when I was at secondary school, we were told to use 'Angkup dalam' or inside caliper to measure the inside diameter of anything with internal surface.

Working in inspection now, we have another tool called Bowers micrometer. It is basically a normal micrometer, but measures the inside diameter, instead of outside. The three-legged probe will expand outwards when you turn the black handle clockwise, until you hear the rat-tat-tat sound, which indicates that you have reached the maximum expansion (the inside diameter). Then, you can read the value, near the handle there. The three-legged system will definitely gives you more accurate reading, compared to the 2 points measurement. Oh, make sure you calibrate the device before taking the measurement, using the calibration block (the block with a centre hole of a specific/ known diameter).

I wonder if the doctors at the General Hospital used similar tool to check on Saiful Bukhari. If so, then we can rename this device as the "Saiful's micrometer". I wonder how they calibrate their device in the first place. How or whose...

Anyway, it is time that malaysians step forward and let the world notify us. Malaysia Boleh!!