Scribing w/the UMM tool is an adventure every Modelet should take.
Here is another tool that you can use for scribing, it’s a fine chisel:
or this one:
We were discussing these on the Maschinen Krieger forum, in this thread:
maschinenkrueger.com/…/index.php
The observation about the BMC blade is that it makes a nice, fine score, because the blade is uniformly thin. It was also noted, though, that some users found the blade had a tendency to break. Others said they had no problems, so, I don’t know. I have one of these on order, but I also use a fine sewing needle, and a Nr. 11 blade for scoring and scribing.