They are a minor PITA but you have to just put them on with extra care such as carefully checking it's located fully as you tighten with the other hand. Once tightened, spin the blades slowly by hand -making absolutely sure the spark plug boot is well away from the plug end, and look carefully the blade carrier is spinning true.
Ahh, if only victa had kept producing the thumblatch catcher series, they would be in better shape today!
