Inside radius gauge.
Fullsize image: https://s3-us-west-1.amazonaws.com/h...e_fullsize.jpg
https://s3-us-west-1.amazonaws.com/h...dius_gauge.jpg
Previously:
https://www.homemadetools.net/forum/...913#post144604
https://www.homemadetools.net/forum/...147#post138276
https://www.homemadetools.net/forum/...673#post147756
https://www.homemadetools.net/forum/...127#post157535
https://www.homemadetools.net/forum/...008#post164540
https://www.homemadetools.net/forum/...870#post167707
