Hi Bill:
Welcome to Phonoland. It sounds like you're relatively new to 78 record collecting. I say this because you said, " currently I am limiting my collecting to 78's prior to 1960." That would actually encompass (virtually) all 78s ever produced.
With the exception of those manufactured for parts of the world where electricity was still not available at the time, such as India, parts of Africa, etc.--SEE: Beatles at 78 RPM --
http://www.cool78s.com/ -- the 78 format had pretty well run its course by the mid-to-late 1950s. In the US, UK and European markets, all of the major and minor record producers had switched to 45 rpm and LPs by that time.
While I don't have any 78s to give away at this time, I wanted to pass this link along to you for your reference. It provides a good dating guide for 78s, and includes all of the major and most of the minor (US) manufacturers --
http://settlet.fateback.com/ BTW, One place you might want to check, from time to time, for free records is Craigslist --
http://www.craigslist.org Rather than search the hundreds of individual forums, you can do an across the board search of the site by going to
http://www.google.com and typing in the following. (This is a case sensitive search.)
site:craigslist.org free 78s OR 78-rpm records
This will call up any craigslist listings containing those words.
Along this line, you can also post a (free) wanted ad on your local Craigslist board.
And, if your local VETS office has a bulletin board, be sure to post a wanted message there. There are still a number of WWII and Korean War vets around who possibly have stacks of old records in their cellars or attics that their kids/grandchildren don't want.
Good luck.
Joe_DS