I did it with my helmet, worked out just fine. In fact I've modified quite a few of my pieces. As long as your knife is sharp and you don't mangle it while cutting it should be fine.
Ooo that's a good one. Satchmo does great work. Thanks eiros I've made a note of it in the armory. When Art Andrews redid the armory he left out a lot of "duplicate" files. I don't think he realized that some of them were different. Like my helmet is Carter's helmet, but with a bill added on top, so it is a different file than the standard one.
You still have snow???At least we have a few inches of snow here so I can stick my head into it. Like this guy.......
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slow moving but I'll get there.