James - I wouldn't recommend using a Dremel for this job doing it the way I did.

You are right to be fearful of a power tool in this context - I was extremely careful throughout the job and was mightily relieved when I had done it! Never again!

I don't have a workshop or even an engineers vise. I think this sort of job is best done when the person doing it has access to these facilities - and a lot of experience too!