I had never heard of this man and find it amazing that with as many knives as he sold there are only a few around.  That must mean they were used, not collected.  If he could only see them now!

JACK KNIFE BEN    
It isn't a knife; instead it is a piece  of knife lore. A March 1927 issue of The American Magazine had a great article
about Jack Knife Ben himself, written by a journalist named  Neil M. Clark. 

    Jack Knife Ben was really named Benjamin W. Chon.
In 1887,  when he was twenty-four years old, Ben Chon "reached Chicago  by box car busted and broke. It was late fall and cold."   His most recent job had been as an actor in a traveling  theater company playing Uncle Tom's Cabin."  He had played  "nearly every role but the bloodhound," but the company had  not earned enough money to pay the actors' salaries.     In Chicago Ben Chon did odd jobs until he had saved eight  dollars. Then he went to visit the giant 
Union Stock Yards,  then the most notable attraction in the Windy City.

 "I was  amazed," said Ben, "at the number of farmers, stock-raisers,  cowboys, and cattlemen who came there from all over. The  thought occurred to me that every one of those men needed a  first class jack knife. I asked myself why they shouldn't  buy knives of me, and get good ones!     
The next morning I was on the job. My store was a barrel, my  display case a cigar box, and my entire stock a few dozen knives I had been able to pick up at a bargain with my eight  dollars. I offered the knives for sale at a quarter apiece.     "At first it was pretty tough, sticking to it through cold,  rain, snow, sleet, and sun. But people got to know me. I  had a line of talk, guaranteed my knives, and took care to  sell good knives, built the way farmers wanted them.  Customers at my barrel store soon included all sorts and  classes, from laborers to millionaire packers and commission  men.     "But I was only a peddler. The policeman on the beat did  not understand my ambitions and hated peddlers -- me  especially. Day after day he'd order me away; and I'd come  back, as sure as the next sun rose. ...    

 "It was about eight years [1895] before I finally got my  first little shop. Mr. John Ashby was then Vice President of  the Stock Yards Company. That company owned the real estate,  and leased it out, and they wouldn't let me rent any 
space,  even after I could afford it. But Mr. Ashby noticed I was  persistent, and he had a little shack put up for me.
 It was just about big enough to turn around in; but I settled in it,  and made money faster than ever!     
 "Later on the elevated lines were built and the steam  railroad was abandoned. I rented the old station, and fitted  it up as a store. We're still in it."       

In 1927, Jack Knife Ben's store was doing several hundred  thousand dollars a year in business. Besides the old  standby, pocketknives, it also sold razors, diamonds,  jewelry, clothing and men's furnishings, rain coats, leather  goods, and optical instruments. As Ben said, "We aren't  grand, like some of the stores downtown. But that's real  mahogany in those showcases; when a jeweler wants to close  out and quit, I can give him cash for his stock -- twenty,  thirty, fifty thousand dollars if need be -- and get bargains  for my customers.    
 "One of my sons now manages one side of the store, and  another has charge of the other side, but I still prefer to  stand out in front with my tray of knives, and sell them to  all comers in all weathers. Seldom a day goes by when I sell  less than fifty knives. I have sold as many as seven and  eight hundred in a single day.    
 "I pride myself on knowing more farmers than anybody else  in the country. ... I have done business with a lot of  famous people, too. Everybody who comes to Chicago comes to  the Stock Yards, and they pass my place of business. The  Prince of Wales has one of my knives. President Harding had  one, and President Coolidge has one."      Benjamin Chon, the little man in the gray business suit and  the blue yachting cap, and with the carnival pitchman's  mesmerizing voice, was for more than half a century almost as  much of a Chicago institution as the Stock Yards themselves.  "Quality, sir?" he often said. "Just read that, if you  please; it says 'Jack Knife Ben' on the blade, doesn't it?   That never goes on a knife unless I stand behind it."    *    *    *   
FROM "KNIFE LORE," NATIONAL KNIFE MAGAZINE, APRIL 1989  JACK KNIFE BEN REVISITED   
 Mr. John E. Thompson of Illinois read my write-up on Jack  Knife Ben Chon of Chicago in the November installment of
 this  column, and it brought back some fond memories for him. He  writes, "I enjoyed this issue, my first, especially the piece  on Jack Knife Ben. I have done business with Ben, or with  one of his sons -- a pocketknife or two, but mostly 
tools of  the stockman's trade, like canes and sorting poles. My dad  bought my mother's engagement ring from Ben about 1919."    *    *    *    also see:
 ATLANTIC MONTHLY, APRIL 1998 pp 71-87  for a biography of Ben Chon's youngest son, 
William Shawn  (1907-1992), long time editor of the New Yorker Magazine.    
 One of the sources for this article was the book:  Men Meat & Miracles, 1952, by Bertram Fowler.     According to this story, Ben Chon was born in Canada in  1863. His wife, Anna Bransky, was born in Manchester, England,  and her family emigrated to Detroit, where they met. 

 Ben Chon retired in 1928, leaving his son Harold in charge of  the business. Jack Knife Ben died in 1952.