The fittings in the link from Old Magnet are far cheaper than any I found when I was looking. Since this topic seems to come up frequently, I will add that this equipment is still available from Cat. The current grease pump offering is Cat part# 7H-1680. It replaced the 1937 style in the mid-1950's, and is still available today, although it no longer comes with the button-head adapter. The button-head adapter is Cat 3F-3915 or Alemite 304301. The adapter and hose assembly is Cat 7H-3933. A couple years ago, the local Cat dealer quoted $38 for 3F-3915, $105 for 7H-3933, or $282 for 7H-1680. The $38 for just the fitting seemed in line with what I found at other sources for a new fitting.

Dave

Last week I bought mine for the "giant" size at Grainger. They had the smaller two sizes in stock and ordered mine. It was in at 9am the next morning. $25.