Bob and Pro are right, we have all faced these issues at one time or another during a long build. It could be a brand new engine that is all painted and installed, but suddenly has a knock deep inside, some suspension component that gets in the way of other stuff, or, in your case, some body problems caused by Mom Nature and 70 years.

Sometimes we have to walk away for a while, be it a day, week, or even months so that we can put the problem into perspective and start anew. Hitting yourself on top of the head with a BFH also helps, as does asking yourself why you chose this hobby in the first place when you could have been holding a fishing pole in one hand and a beer in the other instead.

Don