Count me among those who would have done it the other way Bill.
I would have closed most of the threads in a collet and used my 1.5mm wide parting/grooving insert tool. Can I do it with a file? Yes. I just feel more comfortable using carbide tooling in what can be fairly hard steel. In fact, thanks for sharing that because it really wouldn't have occured to me to file it down. Nice to know there's other ways to do something like that.
I would have closed most of the threads in a collet and used my 1.5mm wide parting/grooving insert tool. Can I do it with a file? Yes. I just feel more comfortable using carbide tooling in what can be fairly hard steel. In fact, thanks for sharing that because it really wouldn't have occured to me to file it down. Nice to know there's other ways to do something like that.