NEW Gillette Blades

[sandmountainslim]

When Gillette released the NEW razor and it's slotted blades in 1929-30 did they immediatly stop producing the old 3 hole blades or did they carry on for a few years afterwards?
Also were other manufacturers able to also make slotted blades to fit the NEW back in the thirties or did they have to wait for a while? I know other companies made them in the forties but was unsure about earlier.
Thanks for any replies.
Wp

 

[AsylumGuido]

Gillette stopped making the three hole blades as soon as the slotted variety was introduced. Note that the three hole blade design was introduced in 1903. They were discontinued exactly 25 years later, precisely when their patent expired. The NEW slotted blades were designed to still fit in older razors. Other companies were able to freely use the three hole blade design after 1928, but Gillette purposely stopped making razors that would accommodate them.