nice idea there.

some suggestions

1. hot zone at the thimble for user to move the micrometer for interactivity

2. the scale is not marked at the 0.00 mm, 10.00 mm, 20.00 mm for the top main scale

3. the sample applet found here has nice design for ease of understanding how to read the main scale with the rotating scale, with numbers to hint the learner.

4. if i see correctly, the readings have a systematic error of +3.00 mm

5. when mouse over, it shows the function of the parts. can refer to this site for the texts. . I can help you do this simple stuff :)

ah, still no html tags ;D has html codes enabled !
it looks cool to applets in forum, the community can help you to populate EJS applets