Until now, the only choices have been to either come up with a salvaged filler unit (at about $35), or to create a replacement out of something close in shape and size. Now there is an easier, cheaper (and, dare we say, greener?) option.
We are happy to offer custom-turned replacement sockets which will fit the vacumatic filler unit, as found in Parker 51s, duofolds, and vacumatics (note: these are not for the speedline or lock-down units). Each is hand-turned out of Delrin, which is strong and durable, and has much more flexibility than the original plastic. Although there are some minor variations, each is fully tested for fit and pellet snugness. Due to the variability in the plunger-tenon sizes we suggest that you use a drop of cyanoacrylate ('super') glue to keep each in place.
Priced individually, includes shipping worldwide. Questions, or Paypal, can be sent to: firstname.lastname@example.org
As a side note, a complete breakdown of a vacumatic filler unit can be found on our site at: http://www.restorersart.com/2011/01/22/breaking-down-a-parker-vacumatic-filler-unit. This may be helpful in visualizing how these sockets are installed.