Finder finds wrong stuff

This may seem rhetorical but I'm frustrated. How do I get the finder to find what I am looking for?

I have multiple Macs with different operating systems from 10.4 to 10.8 (the result of keeping legacy computers and buying used equipment). I've been using Mac almost exclusively since 1994, I guess you'd call me an expert user. The computer I use most often is 10.7, so I'm writing here. I have a lot of data spread across multiple external drives. When I use the find command on any compter after 10.5, the results I get are useless=Hundreds of files that contain . . . I don't know, some of the same letters in my search. When I sort those results by name, the actual (single) word I spelled does not appear in the results. Manually navigating to the drive where I know that file is, I find the file (buried maybe 2-3 folders down). The word I spelled was correct, even to upper case and lower case, but the finder never found IT, just hundreds of junk entries. This situation happens repeatedly. This most basic function of a computer seems to be failing. Is there some setting I have wrong on multiple, newer computers?