OK, I found the original write up and here it is, I hope it's not too ling.
What pen maker hasn't wished they could remove the tranny from a 7mm pen to reset it or to reuse it for another design? I have, and usually tried pounding the thing out or just clamping it in a vise and yanking it out then getting a new transmission. Well I just figured out how to remove the transmission without a small hammer and with very little effort. Check this out:
The first thing needed is the 28 pc Transfer Punch set #3577 selling for $9.99 at Harbor Freight.
To begin, disassemble the pen and remove the ink refill.
Using the 1/8" dia. transfer punch knock out the nib by going through the transmission. (I did say you would need a hammer for this)
Using a 3" block of hardwood drill a 5/8" hole about 1 ½" deep and then drill a ¼" hole the same depth through to the center of the first hole.
Now we insert the tranny still in the lower part of the pen into the ¼" hole. (Using a small dowel wrapped with sandpaper to smooth the 1/4" hole will help.)
With the drill chuck in the tail stock install the 15/64" transfer punch, flat end out.
Slide the transfer punch into the blank sticking out of the block of wood and slide the whole thing to the head stock.
Almost finished; lock the tail stock with the block against the head of the lathe and begin cranking the quill. When you get to where the cranking resistance loosens up the transmission has been removed. You will usually find it in the 5/8" hole and it can be retrieved and reused.
So there you have it. Hope it helps someone.
WB
If you want, or need, the original post with photos pm me and I'll email it to you.