Wonder why more early bike mechanics have not committed suicide. I'll be first to admit that I am a novice at this but if every business was run like the road bike business was, there would be a lot more waste and expense then necessary. The lack of standardization always puzzeled me but I just took it with a grain of salt (what does that mean anyway?)
Okay, I was working on a bike to install a triple TA crank and rings on it. First I needed a BB for the job and I used the W-DIH method. You know, look in the bin and see What Do I Have. Since I have several BBs I did some basic measurements and found one that came close. After installation I found that although the spindle was what I wanted the taper was not. The crank did not even make it half way to be seated. Out it came and now I am smarter so I go with one that seats better before I install it. Okay now install the cranks. Of course I installed the non chain side first. When I installed the chain side I noticed that there was still a huge gap from the BB to the crank. No matter, I will continue and give it a try. Took it for one ride and it rode like a pig. Chain alignment problems and ankle biting because of the extended crank. Out it came. Next I went to my LBS and told my tale of woe. We measured up correctly and found a spindle that should work. Installed it and all seems well. Nice close fit from the bb to the crank. Very much improved chain line so I thought I was all set.
Well in trial shifts I noticed that the front rings shifted terribly (Using a Campy derailleur with a triple 26-36-46. It seemed that I could jump to the smallest and largest rings but could not get it to grab that middle ring. Explained this situation to my LBS who explained that there was to much a gap from the middle ring to the largest ring and he suggested making the middle more like a 44 and that would improve the situation. Well I got lucky on ebay and found another TA triple ring set and got it for a good price. Today arrived a 36-46-50 with the closer tooth combination that should work.
I installed the new rings on the crank. Now mind you this is an exact switch of TA for TA. Same spindle and all. Now when I install the crank on the BB the smaller ring hits the frame. It was a good 3-4 mm away before but now it interferes. I am about to take out the bb again and go with another one. Sooner or later I will hit on the right combination but did not bank on this becoming my own version of rubiks cube.