Parker Clip Bushing

Available in 2 sizes. Both bushings use a 10-32 outer thread.
BUSHING A: These have the more commonly used smaller diameter inner threaded hole. The outer thread fits most standard sized Parker fountain pens and also pencils and ballpoints. Pairs with our 51 Clip Screw/Jewel.
BUSHING B: These have the larger, less commonly used 4-40 threaded inner hole.

Here are some notes from Ron Zorn on jewel & bushing threads: "The larger 4-40 holes for the stems were used on the second generation Vacumatics and on the Vacumatic filled  Parker 51.  They changed to the smaller stem and thread size in the bushing with the aerometric 51.  The threads on the outside are indeed 10-32, but if you have an aerometric, you'll need the smaller A bushing."

You CAN use different threads than what were originally used by changing the bushing thread size; this is needed if you are using our grey/silver jewels for Parker 51 caps, you may need to do this if you need to put one of our repro 51 jewels/clip screws on a 51 cap that has a 4-40 hole, you may need to change out the 4-40 bushing with a 3-56 bushing.