FAL, I like your last analogy, and I think it truly reflects a Christian's life.
What you seem to have forgotten however is that you were not always a "master" machinist. I bet that 40 years ago you thought you were a pretty good machinist, but NOW you know better.
It is the same with Christians, you do not become perfect overnight. It takes patient continuance to mature as a Christian, just as it does to be a master machinist.
I have always loved Psalm 1, I believe it applies here.
Psa 1:1 Blessed is the man that walketh not in the counsel of the ungodly, nor standeth in the way of sinners, nor sitteth in the seat of the scornful.
2 But his delight is in the law of the LORD; and in his law doth he meditate day and night.
3 And he shall be like a tree planted by the rivers of water, that bringeth forth his fruit in his season; his leaf also shall not wither; and whatsoever he doeth shall prosper.
FAL, it takes a long time for a tree to grow, it does not spring up overnight. Be careful not to judge your fellow Christian, many are just saplings starting out. Be kind and guide them along, not harsh and condemning.
You don't expect a new machinist to be as skilled as you are, do you? Didn't think so. You help them, don't you? Be the same as a Christian.