Run out error causes various vibrations and noise in the gear mechanism. To completely remove it, the manufactured gear is hardened, and then grinded. Grinding removes this error completely, and hardening prevents it to get oval after gear mesh when used. One example of use of such gears is below in the photos.The gear in the photo is, used in pump for hydraulics. In order for gears to create the sufficient pressure, it should have no run out error.
There are various ways to measure it, such as computerized machines which work with air pressure and give whole reading of gear teeth profile and run out. Most often it is measured by indicating the position of pin inserted in each tooth space around the gear and taking the largest difference. Another way is, generally for fine pitch gears, to roll the gear with master gear on a variable centre distance fixture, which measure and record the change in the centre distance as the measure of teeth or pitch circle run out.
The method that I used here is a simplest one, and the most fastest. I used a screw gauge and measured the run out in each of group of three teeth, I selected the number 'three' for screw gauge to measure the error with MOT formula. The cutting and grinding of teeth was done in the company. The Reading was found to be 34.44 in each of group, and hence the run out was 0.
