The company has many machinists that are allowed to use their own measuring instruments. I would like to apply a 'Calibration Not Required' label on most of these. Would this be acceptable by AS9100 standard?
Clause 22.214.171.124 on measurement traceability requires calibration for any equipment that is essential to providing confidence of the validity of measurement results, or in other words measuring equipment used to make official measurements. If the tools you are speaking of are used to make the final measurements that are ensuring final validation measurement on a product then they would need to be calibrated. If they are only reference measurements to ensure that future official measurements are correct then deeming them as calibration not required would not be against AS9100 requirements.
For a better understanding of the AS9100 Rev D clauses, see this whitepaper: Clause-by-clause explanation of AS9100 Rev D, https://info.advisera.com/9100academy/free-download/clause-by-clause-explanation-of-as9100-rev-d