My tool for pulling sq taper cranks has a removable end as well, with 2 to choose from. One works on narrower opening and one for larger (later model) BBs. I always have to check before threading it in that the part that contacts the axle does so without touching the crank taper. Another favorite error of mine; forgetting to ensure you take out the washer for the crank bolt and trying to remove the cranks with the washer still in place. Doesn't work well, to say the least, but it does result in some interestingly shaped washers..