Back in July of 2020 I got a call from Bill Wahl of Mesa Typewriter Exchange to let me know that the IBM Selectric I dropped off was done. There have been a few of these iron giants in my collection from time to time, but this one is the one I keep. While not particularly pretty (Like Teds blue-key beauty), it’s clean and a good size. Sadly, it had developed a bad case of Selectric thumping and was giving me some problem with the ribbon advance mechanism. This one uses the carbon ribbons. Both of these repairs are not in my bailiwick so to Bill it went.
Bill replaced the cycle clutch pulley gear with a new non-broken one. For anyone who has ever owned a thunking Selectric, you know that it’s a matter of time until this part breaks. Age is the culprit. Time is not kind to the plastic and it becomes brittle. Sometimes you can repair them with epoxy and binding wire, but replacement is the only guaranteed option for trouble-free typing.
With all the OEM parts used up or aging and cracking on their own, modern manufacturing processes can breath new life into these typewriters. Bill gave me a small tour of the two types of replacement pulleys available today. One is CNC milled aluminum and the other is 3D printed.
In the picture above, you can see the CNC milled aluminum example (top) and the 3D printed one below. The original cracked part is brown. Having used the aluminum parts initially, Bill prefers the 3D printed ones; they are less noisy.
Both of the replacements pulleys need a donor arbor to mount them properly. The new pulley feels like sintered nylon to me, but it might be another material. Regardless there is a heft to this replacement part that makes it feel like a quality item. With only dozens of these parts in working typewriters the longevity is still an open question, but based on how mine works and sounds I think it works well and if something happens another one can be printed.
The promise of rapid prototyping and the 3D printing makes it possible to keep our old typewriters running. It only takes someone who knows what they are doing and cares enough about our magical writing machines to help keep them humming along sans thump.
