Originally Posted by Nyah

Here's the story and the components that people are asking about:
I got the frameset new and added all the parts (everything new, except for crankset and some unrelated parts). Everything went well for me (even the wheel-build), with the exception of the rear shifting. LBS took a look at it and recommended a new R derailleur. I had them choose one based on my intent and had them tune it. They did a good job and I enjoyed riding the bicycle for a few days.

After that, I had to get a repair done to one of the threaded braze-ons, which required that I remove the RD and almost everything else. That repair was successful and now I'd like to finish this bicycle myself. I've never had full success in setting up RD shifting. My other bicycle which I've tried this has a stubborn cog which I just skip over when riding. Maybe I can fix that one after gaining new experience with this one.

Rear derailleur is Microshift RD-R43M. Brand new.
Shift lever is Microshift BS-T09. Brand new.
Cassette, 9spd, is a take-off from a new bicycle. I test rode that bicycle but upgraded it immediately to a different number of speeds.
Chain, 9spd, is new, the correct number of links and working smoothly.
Cables and housing are brand new, Jagwire.

I will now try to see if the built-in (CrMo frame) D hanger got bent.