Around 1891 or 1892, Kopf moved his reelmaking to a factory in Whitestone, Long Island, owned by U.S. Net & Twine Co., which became the sole agents for Kopf's reels. Nevertheless, he was forced to declare bankruptcy in 1893.
  Kopf returned to Brooklyn, where Kopf & Ottmann sold tackle for a couple of years. When Ottmann left the partnership by 1896, Kopf established Kopf Reel Works, where he was joined by William Kopf, his brother or cousin. At the turn of the century, Kopf was still making fishing tackle, but he probably no longer was making reels. He declared bankruptcy again in 1900.
  Kopf made reels with hard rubber, plain or plated brass, and German silver. He was one of the earliest reelmakers to use Celluloid for sideplates. Some of his later reels were made of aluminum. Few reels were marked with Kopf's name, and even then, some were marked inside. Many Kopf reels, lacking maker marks, patent dates, or recognizable patented features, often remain unidentified.

The reel section of a rod-and-reel combo made by Kopf. The "Unique" combo came in a wooden case patented by Kopf and sold by U.S. Net & Twine.

A plated-brass S-handle marked "John Kopf/Maker" on the headcap.

An aluminum and brass multiplier made by Kopf. The foot resembles his patented corrugated foot but is a solid casting. The spring brake is featured in his third reel patent.

The headplate of the aluminum reel is marked with Kopf's name. Many of his better reels included housings for the pinions.

A Kopf reel with Celluloid sideplates and crank knob.

Various sliding buttons are seen on Kopf reels.

A Kopf plated-brass and hard-rubber reel, marked with the name of H.H. Kiffe, a major New York sporting goods retailer.

An "Acme" fly reel with a wire spool,
made by Kopf.

The interior mark on the headplate
of the raised-pillar reel.

A Kopf plated-brass raised-pillar reel.

Another aluminum and brass reel, also marked inside.

Back of the aluminum reel.

Tailplate of the aluminum reel.