My IMS CO2 Car/F1 Car fixtures are really frustrating me. Since the base and end blocks are made of aluminum, I cannot tighten the thumbscrews enough to keep them from working loose while the car is cutting out. I even retighten/snug them between sides. This has happened multiple times. I was having success with my first cars, but the more I use the fixtures, the more trouble I am having. The threads are NOT stripped yet. I learned that lesson already and had to replace one of the fixtures.
Love the machine......hate the fixture!
