On our Haas TL-1. In exchange for letting us use the Buttonwillow kart track for free, we agreed to make a part for the racecar the guy who runs the kart track owns. While I was slightly annoyed because nobody on the team notified me of this plan (and I'm the only one who can run the CNC lathe), I made the part. This is just the mold over which carbon fiber will be laid to create the part. It was a bitch to machine because the stock was 5" and the jaws on the vise only opened about 4.75" in their un-flipped orientation. I had to flip the jaws (which means only holding the part by 3/8", and when it's a 25 pound hunk of aluminum spinning around 800 RPM, that's sketchy), turn an inch of it down to 4.25", then hold that in the jaws normally and machine the rest. Bit of the process, and I made a whole load of chips, but it was good experience.