Although early grinder/sander units were manufactured in the 1940’s and 1950’s, it was not unit the later 1950’s through the 1970’s that huge numbers of combination units were produced.
The largest of these were Highland Park Manufacturing Company, Frantom Lapidary, Star Diamond, Beacon Star Lapidary.
There were also many other small manufactures.
One thing to remember is that vintage lapidary equipment manufactures of combination units were often changing and adding on components mid-year so model numbers rarely tell us the whole story of schematics.
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