Burnhard,
WELCOME TO THE AWS WELDING FORUM!!Thanks for coming here to get your questions answered. It is indeed a great place to make a regular source of information for all your needs.
Everyone has made some great points. Let's see if I can muddy the waters, I mean, add more to your info base.
1) There is no restriction in D1.1 as to tools compliant and/or restricted for welder performance qualification.
a. True, it is curious as to why one would and another doesn't. Bridges would more regularly have hard to get at joint configuration is my 'guess'. D1.1 not so much unless it was also a D1.8 qualified joint where you have restricted access and additional testing required because of seismic specifications.
b. Grinders, air needle scalers or chipping guns, slag hammers, wire brushes- hand or on a grinder, etc are all fair game unless the WPS or other instructions to the welders state otherwise.
2) Inspectors need to make sure of their responsibility before getting into the middle of something.
3) Inspectors need to make sure of all customer expectations and requirements before starting a job.
4) It is not a grinding test, it is a WELDING test.
a. Having quoted a well known contributor here, it is still important to make this requirement known ahead of time and only if the customer so wishes it.
b. For a shop environment where they would have easy access to all these different tools, why would one restrict them even for a test. It could be said that the Bridge Code goes out of it's way to make sure a person can accomplish his appointed task with what is seen as a minimum amount of equipment because they could get caught in a situation where that was all they had available with no power, air, tools etc to use all the others. So, they make sure they can pass the grade with a minimum. Most fabrication is done in shops for structural steel and they have easy access to these. Comparatively.
5) Why a 3G on a 2" plate? For welder quals you only need a 1" plate for unlimited qualification. Per D1.1. The test should be done with 1" (25mm) then if the employer wants additional testing on heavier components to verify the welders can keep the joint straight after all that stress is added to the joint it is his prerogative to do additional testing and restrict welders from jobs they are not capable of completing properly.
6) Tests should be used as slight educational moments. Pointing out the variables in the Codes will help the welders understand why one time they can do something one way but the next time they have to do it differently. Such could your point at the restriction of tools in D1.5 be taken. But make sure you know where you are going and the acceptable means per the code you are asked specifically to work to.
Again, welcome. Hope this is helpful.
He Is In Control, Have a Great Day, Brent