Good point ... use @ the one in poor shape as a "parts car".
I personally just don't have the tools to fabricate parts. It was a godsend for me to find a source for the release button. I had scavenged the 2 previous buttons from inexpensive Chinese units. I had to chuck these little buttons up in the drill press & file a couple of the OD's down ... but ... the worst thing was they were too soft to last very long.
I could find very few commercially manufactured replacement parts. The other sources I did find were either off shore or apparently reselling knifekits.com's parts.