Yeah I did the same mod to my nosepiece under Paul's expert remote guidance and encouragement.
I used a bench grinder though. I found I also had to shorten the nosepiece as well. I think it measured something like 6-7mm longer than Paul's and stopped the camera getting as close as I needed it. If you do have to shorten the nosepiece, use an old piece of hacksaw blade to clean out the thread after you've ground it.