(Updated 9/17/10 6 PM PST)
The history of the KM Pro Company goes back to 1896, when Tim McAuliffe Inc., a manufacturer of sporting goods was founded in Boston, Mass. McAuliffe supplied caps and uniforms to many sports teams, specifically baseball.
In a time when New Era was supplying caps to only a small number of teams, McAullife was king. McAullife caps weren't always manufactured by the company themselves. McAuliffe caps were often made under private label by companies such as Leslie and even New Era.
McAullife's embroidery was provided by the Roman Art Embroidery Company, also based in Boston. All teams until expansion in the 1960s used McAullife caps at one time or another.
Downsized by competition, the McAullife name was gone by the end of the 1960s. At that time, they became the KM Pro Company (Does anyone out there know what KM stood for? Because I have no idea). KM caps are most easily recognized by their unique "zig-zag" backing pattern.
The KM Pro Cap Company Held it's ground into the early 1970s providing caps for three of the four 1969 expansion teams (the Expos, Padres, and Pilots (and then the Brewers)) and supplied several major teams as well, including the Boston Red Sox. However, their main competitor New Era finally knocked KM out at the end of the decade and the KM Pro Cap Company closed its doors. Due to the major loss of business, the Roman Art Embroidery Company began manufacturing baseball caps in KM's place and the Roman Pro Cap Company was created. The first Roman caps were identical to KM caps but Roman switched to their own design by the 1980s. That decade, Roman began making reproductions of old-style caps by using their archive of McAullife and KM cap embroidery designs. The rest of the story of the Roman Pro Cap Company has already been covered here. Below is the inside of an example of an early Roman cap identical to a KM cap in every way except the label.
Here is an odd one: Collector Steven August has what appears to be a KM & New Era hybrid. It's a game-used New York Mets cap with a KM-style backing and visor, but with a New Era label. Compare the hybrid to the standard New Era on the right side.
BONUS FREEBIE!!! When new, KM caps came with an insert to help the caps maintain their shape. Make your own by printing out the scan of a real KM cap insert. Just print it out on some card stock paper, cut it out, and fold.
Update: A reader sent me a link to the Game Used Universe forums that prided me with some good info on KM Pro.
"KM pro was a joint venture ( for lack of a better term) between Tim McAuliffe and Jack Kaufman. Hence the K M. The hats were produced by Kaufman and sold thru McAuliffe. The embroidery on the hats was done by Roman Art who also did the chainstitch NIC- NIT on the McAuliffe jerseys. Roman Art also produced for McAuliffe/ Stall and Dean all of the patches that weren't MLB mandated. In the mid '70's the New Era owner David Couch purchased at a bankruptcy sale, all of the Kaufman cap manufacturing equipment possibly in an attempt to eliminate competition in that area."
"I used the term "joint venture" because I lacked a better description. The original McAuliffe Co. didn't mfr anything- jerseys hats ect were all done by someone else. Starting in the early '50's the jerseys were mfr'd by Stall and Dean. I don't know how far back the relationship with Kaufman goes back but they did the hats. In 1969 the McAuliffe "label" was taken over by Stall and Dean and they continued the relationship with Kaufman until the mid '70's when the Kaufman assets/equipment was bought by the New Era owner. All of my KM info came from Richard Stall, the former owner of Stall and Dean."
I have also heard that "KM" stood for Tim McAuliffe's wife, Kim.
A special thanks to Steven August and Ted Weisbrich for providing pictures of KM caps from their respective collections.