This is the latest set of parts I made for my plotter. The left of each pair of parts is the original. The extra little parts in the top middle go inside the top to the left with a spring to push down on the pressurized ballpoint pen. The middle top are the plungers for the pressurized ballpoint and the right top the felt tip pen plungers. The bottom left is a top for felt tip pen. I made mine all out of steel. The original top is anodized aluminum and the center spring loaded piece which pushes down on the pen is plastic. On the right is the retaining nut for the liquid ink reservoir on the plunger. I wasn't able to make the plunger (not shown) since it needed M7x.7 threads which a tap isn't available for and the lathe I am using can only do inch threads.
The parts need some further work such as drilling for the pin in the felt pen top, polishing, plating and final assembly. I also need to find appropriate springs.
Feel free to contact me, David Gesswein email@example.com with any questions, comments on the web site, or if you have related equipment, documentation, software etc. you are willing to part with. I am interested in anything PDP-8 related, computers, peripherals used with them, DEC or third party, or documentation.
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