In a small workroom on Pell Street in Chinatown, Evan O’Hara bent over a scrap of skin from an alligator’s leg and used a large cotton swab to dab it with electric orange dye. Nearby, Janos Papai was pushing a hulking, ancient-looking machine over another scrap of bleached alligator, stitching on a zipper.

Mr. O’Hara, 39, is a leather craftsman whose exclusive custom creations range from $1,800 pickleball racket covers to purple ombre McLaren racing car seats. Mr. Papai, 68, is his mentor.

The two men met 15 years ago, when Mr. O’Hara was a junior employee just starting his career, and Mr. Papai was a factory owner in the garment district making leather fashions for designers like Ralph Lauren and Marc Jacobs. Mr. O’Hara began hanging around Mr. Papai’s factory, asking the veteran craftsman questions and watching him work. Soon, an informal apprenticeship began.

“He was a young kid, curious and polite, and I wanted to help the younger generation,” said Mr. Papai, who immigrated from Romania in 1984 and started out sweeping floors before eventually buying the factory where he once worked.