From Joseph Doddridge, "Notes on the Settlements and Indian Wars of the Western Parts of Virginia and Pennsylvania from 1763 to 1783...", discussing his father in his older years:
"Not possessing sufficient health for service on the scouts, and campaigns, his duty was that of repairing the rifles of his neighbors when they needed it. In this business he manifested a high degree of ingenuity. A small depression on the surface of a stump or log and a wooden mallet were his instruments for straightening the gun barrel when crooked. Without the aid of a bow string he could discover the smallest bend in a barrel. With a bit of steel, he could make a saw for deepening the furrows, when requisite. A few shots determined whether the gun might be trusted."
Spence
"Not possessing sufficient health for service on the scouts, and campaigns, his duty was that of repairing the rifles of his neighbors when they needed it. In this business he manifested a high degree of ingenuity. A small depression on the surface of a stump or log and a wooden mallet were his instruments for straightening the gun barrel when crooked. Without the aid of a bow string he could discover the smallest bend in a barrel. With a bit of steel, he could make a saw for deepening the furrows, when requisite. A few shots determined whether the gun might be trusted."
Spence