i have a 4.5" angle grinder that i want to put a 7" cut off wheel on to chop a bolt off. the 4.5" wheel is not big enough and wont reach the depth i need. can i safely use the larger wheel on it? they are both type 27. i tried google but could not find an answer. i tried a reciprocating saw and the grade 10.9 bolt chews up the blade pretty quick.