Okay, for all who gave me advise and for anyone else who might be interested in the trials and tribulastions of rechroming here is an update.
I am happy to say that the stem now fits - after many, many evening spent with metal files and emery cloth and hands ripped down to blisters. I eventually removed the plating from roughly 7cm at the bottom of the quill! Here is the issue - the triple plating (nickel, copper and chrome) was the problem when it came to increasing the quill diameter. In some parts I had to remove the chrome and the copper down to the nickel. The other issue was that the quill was not round - thus, requiring removal of more plating in places. I have now a functioning stem which has plenty of new chrome left on the quill above the insertion point.
I will know better next time - I guess that the stem is probably one of the more crucial parts to get right given the need to insert in steerer as well as through the locknut!
Blisters are now healing!
Paul B. Williams, BAH, MPhil, PhD
Ottawa, Ontario, Canada