- Joined
- Jun 12, 2014
- Messages
- 4,812
I agree, you are seeing around 0.0002 and maybe a little more with the 0.0001" test indicator. Also, a test indicator is more useful for relative movement as opposed to absolute measurement due to the angle of the tip to the work and the change in accuracy with swing. You also have some inherent +/- tolerance for the rated indicator.
I also agree that you can easily be deceived measuring anything when you are measuring outside the rated spec for the indicator. I had a similar issue trying to setup the stylus tip on edge finders which required to be within 0.0001" concentric. I tried with a Interapid 0.0005" indicator and kept on getting errors with the edge finders (both mechanical and electronic). I broke down and purchased a Compac 215 GA and it solved the problem because the accuracy improvement. What I like about the Compac 215GA is a large easy to read dial, and a range of 0.024", so much more forgiving. If I need to do direct measurement I use my Starrett 25-511 and 25-611 dial indicators, these do a great job of measuring down to 0.0001" with a 0.200" indicator range. So one dial indicator pretty much does it all for me.
I also agree that you can easily be deceived measuring anything when you are measuring outside the rated spec for the indicator. I had a similar issue trying to setup the stylus tip on edge finders which required to be within 0.0001" concentric. I tried with a Interapid 0.0005" indicator and kept on getting errors with the edge finders (both mechanical and electronic). I broke down and purchased a Compac 215 GA and it solved the problem because the accuracy improvement. What I like about the Compac 215GA is a large easy to read dial, and a range of 0.024", so much more forgiving. If I need to do direct measurement I use my Starrett 25-511 and 25-611 dial indicators, these do a great job of measuring down to 0.0001" with a 0.200" indicator range. So one dial indicator pretty much does it all for me.