John Hancock Cartridge Pen Full Breakdown

July 22, 2019

While The John Hancock copper cartridge pen by Pollack Pen Co Boston is not a common or popular pen, I could not find any information about how to break it down to clean and possibly restore it. There was a helpful post by David Nishmura from 2010 informing us that the section is integral to the barrel, and another post with some history and overview, and one more listing the patent number. US1,671,125,

There is a hard rubber pin that hold the section in place. It needs to be removed to do any work on the pen. On one of my examples, a tiny eyeglasses type screwdriver could be used to pry it up by working it in between the feed and the pin and slowly working enough out to grab with a needle nose pliers to remove the rest of the way. The other pin in the other Hancock pen would not come out this way, and I drilled the middle of the pin with a tiny bit and pin vise, and at some point, it pulled out with the drill bit.

At this point, the nib and section can be worked out of the pen.

Inside the section is a collar with a matching hole to the section. At the inside end of the collar are the threads for the copper cartridge. The collar has a step down in diameter inside, as does the feed. With the feed maximally inserted, there is a few mm protrusion of the feed, which serves to puncture or pop open the cartridge when it is firmly screwed on to the threads of the inner collar.

The collar can be knocked out once the pin is removed as well as the nib and feed. I suppose with the correct size hollow punch, the collar could be knocked out without removal of the nib and feed, but the pin would need to be removed anyway.

The cartridge is thin and delicate. The threaded end is created with an insert that is threaded, and abruptly steps down to a narrowing the size of the narrow inside end of the feed. My intact cartridge has a tiny round piece still inside rattling around that looks like it once sealed the cartridge and was knocked inside by the feed when the cartridge was inserted.

Since my other cartridge was mostly ruined and also was stuck to the collar, I dissected it to get it off as well as take a closer look. The threads and narrow aperture are a single piece inside the hollow copper cartridge. The material was soft and reminded me of lead (but I have no means to test it).

Once I had the pen apart, the reason for the hard rubber pin became clearer. Without it, screwing in the cartridge would likely just push out the feed and fail to open the cartridge, or would push the entire collar and feed out of the pen. The pin keeps in place the narrow protrusion of the feed and holds all the pieces together so the cartridge can be forcibly screwed in place and popped open without ejecting any of the parts out the section end.

I believe that the attached pictures will help anyone else trying to take the pen apart to better understand its construction.