Disassemble a Pen
Sometimes it is necessary to disassemble a completed pen to repair a component or restore the finish. This can be done with a "Transfer Punch Set". Remember that you may have to glue in the fitting after repairing the problem with the pen.CA can be used for this purpose, but be sure to put glue only on the inside of the brass tube. Do not get any glue on the out side of the barrel or fitting.
Pressed in transmission
Pressed in transmissions have a small hole in the center of the transmission. Remove the ink fill cartridge, and insert a 3/32 inch punch through the transmission. Gently tap on the end of the punch with a small hammer. Many light taps are better than one great hit. Hold the pen tube firmly over a soft surface to catch the nib. Now use a 15/64 punch to tap out the transmission from the nib end of the pen. 15/64 is the correct punch for a 7 mm brass tube.
Tip: Insert the barrel into the open end of a balloon. The balloon will give you a good grip on the pen barrel and the closed end of the balloon will catch the fitting you knock out.
There is also a way to pull out the transmission which does not involve removing the nib. Drill a hole in a scrap of pen blank that closely fits the transmission. You will have to take into account the kerf of whatever saw you will be using to cut the piece in the next step AND the narrower the saw kerf, the better. For a 7mm transmission, the diameter closely matches a letter "D" drill bit.
Make a witness mark on the piece so you can get it back together again in the same orientation.
Saw the piece in half lengthwise so you end up with two pieces that have a u shaped channel in each piece.
For a 7mm transmission you will need 2 or 4 6mm ID washers. You will need two flat bladed screw drivers of about the same blade size.
Assemble the clamp as in the photo. Insert the ink fill into the transmission and twist to extend the ball point. Put the 6mm washers over the transmission. Clamp the blank around the transmission so there is a narrow space between the washers and put it in a vise. Clamp down on the vice.
Now insert the blades of the screw drivers between the washer and twist the screw drivers in opposite directions. I couldn't hold the camera and both screw drivers at the same time due to a lack of a third hand :) You will easily be able to adjust the transmission to the correct position. Now put the pieces into a pen kit baggie and mark it for 7mm transmissions.
To remove components, use a punch that will fit through one end of the fitting, twist it to catch the lip of the fitting at the other end of the tube, and tap gently in a ring around the fitting. The second fitting can be removed with a punch will just fit into the brass tube. When removing a finial, use caution because some finials are multi-part assemblies, and removal can cause the assembly to come apart.