It's probably impossible to get a perfect 45 degree angle. Even a lab environment could probably only get it accurate to some high number of decimal points.
As long as I have a better lab, I can prove it wasn't 45 degrees and hence would be invalid.
Anything outside of 5 arc seconds from 45° is considered a supplemental contract, which would require initial from the revisor and initial from the district attorney's office, magistrate, governor, or sheriff. This is all established under the contract law established under the 437th revision to the code of Hammurabi under the Governor's office of Antigua, codified by Sir Thomas Warner.