Measuring a Straightedge with a Precision level
36:00
Repeat O Meter
18:06
Reading Optical Flats Part 1
6:11
How to Calibrate a Precision Machinist Level
14:38
Russian Optical Flat Testing
25:40
Precise spirit level
16:46
Autocollimators 1: Introduction
10:59
Machinist level with a perfume vial
8:31