I thought this group might be able to appreciate this part. I ordered 5 from PCBWay. They are 1/4" mild steel. For just over $30USD each I got them in 16 days. But I have SO MANY questions about their process.
I wanted to share my incredulity with group that might also have their minds blown with this.
No clue. Maybe they have a ton of one size endmill and that’s all that’s loaded… Doesn’t really make sense though, would be simple enough to swap the tools in setup.
Only thing that does make sense is they were doing another job with the same material and needed just that finish, or were out of slots in the changer, etc.