“Roland” 1957 Tower Commander – Pica Typeface, “Regular” Linespacer 
“Einstein” 1956 Smith-Corona Silent – Elite (math) Typeface, “Line Saver” Linespacer 
“Bubbles” 1960 Smith-Corona Galaxie – Artistic Script Typeface, “Magna” Linespacer 
Excerpts from The Smith-Corona Floating Shift Typewriter Repair Bible
Printed & Coil-Bound
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Joe’s video on “Slow Your Roll” 1 1/2 linespacing on full-spacing US-Made typewriters:
Interesting. I only knew of newer American machines having 1/2 line spacing.