I have to change my answer from the portables I previously mentioned. I recently got an 1948 Underwood Standard in great condition, and after really thoroughly cleaning all the internals, it is now by far my best typer. The action is almost effortless and it almost wills your fingers to move faster. The segment shift is so smooth, unlike many portables that I find to be a bit jerky. The best part is that even though it is a standard, it has a smaller footprint than some of my portables e.g. the Hermes 3000; it's just taller and much heavier, but it still fits on my small desk fine. 

=14pxI recently purchased (luckily very cheap) an Olympia SF that I could tell immediately was going to present a major challenge. The carriage would basically not move if the escapement was engaged. Given the design of this machine, I really needed to remove the carriage in order to see what was going on with the escapement. What I found was very unusual and disappointing. The escarpment wheel would in fact not turn at all. I tried lubrication to no avail and just couldn't figure out why it wasn't budging. I then decided to unscrew it to see if there was just a bunch of gunk underneath. As I turned the screw, I noticed that it would alternate between turning easily and becoming very difficult to turn every half turn. When I got it out I realized why; the screw itself was badly bent! i assume this means this carriage must have taken quite a blow at some point during shipping. I was wondering if anyone is able to spare that escapement screw from a parts only machine? Otherwise I'm afraid mine will become nothing more than a paper weight.

I recently acquired an Olympia SM7 that seemed to be working fine, until it got to the end of the page, and the carriage would no longer move. I found out that the main spring must have come loose within the drum. I removed the draw band from it's attachment on the carriage and when I tried to rewind the the drum, it just keeps clicking and loosing tension after one spin. I've looked into opening up the drum, but this sounds like a total pain. So wondering if anyone has extra drum lying around that you wouldn't mind selling  

I just bought an Olivetti Underwood Studio 44 that is in good working condition, but unfortunately the plastic paper holder on the left was broken off. I've attached an image in case I'm using the wrong terminology for this part. This is probably why I got it for a pretty good price on eBay. I was wondering if anyone has one of these lying around and would be willing to sell it?