Tuesday, July 7, 2009

Four-Row Underwood

It showed up the other day, a later Underwood portable in green(!) wrinkle(!!) paint. Looked pretty good in the photos but the keys and strikers proved to be frozen up. H'mm, maybe put it up on an auction site?

Might as well see if it'll wake up, first. Spent all of ten minutes soaking the moving parts with very light oil and working the mechanisms and it freed right up. There are still some issues -- one letter's striker typebar is loose (hello, Tix solder!) and it will need some realignment to keep it from sticking -- but it's the usual built-like-a-tank Underwood.

After getting it going, I took a long look at the Mysterious Inner Workings. The typical ribbon advance and reversing mechanism on small portables uses a sliding linkage to move right-angle gears into (or out of) mesh at the ribbon spools. So (generally) there's a long, transverse rod or shaft that moves a short distance back and forth in the same direction as the carriage and it gets rotational drive from the same setup that advances the carriage when a key is struck. See the rod and tiny gears?
It's pretty obvious on this Underwood but drat! It wouldn't slide back and forth. More stuck stuff? Bumped it and something went click....Oh!See what it does? Rotational drive is at the center, a little hand like on a revolver that advances one tooth per letter and the shaft is pivoted at that point! To change ribbon feed direction, the shaft pivots away from one gear and into mesh with the one on the other side. Pretty tricky! The 90-degree drive is a worm type, with a helical "tooth" on the shaft, rather than the more usual flat-cone method.

Word to the wise: Don't play games involving mental agility for money against retired Underwood design engineers.


  1. That's just pornography, is what that is. You naughty thing, you.

  2. I just got a 1941 Champion lastnight in gray. Could you recommend some sites with technical info, I need to unstick a key (E) & get tension in the ribbon and I've had poor luck trying to find a diagram or explanation. It looks like where the key is sticking is back under the carriage. I also want to learn for maintinence so I don't have to find a repair guy if the elastic/fabric snaps. It is indeed an amazing machine, using a simple bar with a little rotation to change typing pressure.

  3. TheAxe, the place to start would be Ricard Polt's collection of tips and links here: http://site.xavier.edu/polt/typewriters/tw-restoration.html. If there's a typewriter repair shop close to you (they show up all over!), sometimes the guys there will offer helpful advice -- this depends on the person and it can sometimes help if you make a small purchase like a ribbon or cleaning supplies.

    The kinds of sticking I find are caked-on ink/oil/lint (most common), peening of the typebars (especially on Underwoods, which have a very tight "gate" that locates the bar right under the type as it hits the paper) and, very rarely, loose parts that get bound up in one another. The first is fixed by using a light oil with some solvents -- Break-Free CLP is good -- and a a small, stiff brush, plus gently working the stuck parts. Peened metal bits can be *carefully* filed back smooth. As for stuck mechanicals -- as a child, did you like those metal puzzles that have to be unsnarled to solve them? :)