by (one's) fingertips
1. Literally, of a grasp, using only the tips of one's fingers (such as when hanging on the edge of a cliff). The stranded hiker was clinging on by her fingertips until the rescue crew arrived.
2. In a way that is narrowly avoiding problems or failure. They're clinging on by their fingertips out there—the other team's offense is totally overwhelming them. Now that I have three small children to care for, I feel as if I'm hanging on by my fingertips every day.
by your fingertips
only with difficulty; barely. 1990 Current History In early 1988 , United States Assistant Secretary of State Elliott Abrams said that General Noriega was clinging to power ‘by his fingertips’.