Knifeblades and Bugaboos - In 1959 there were 2 sizes of Knifeblades and 6 sizes of Bugaboos created. This version had a more square design to the piton eye since each blade was cut by hand. Yes it gets confusing to figure out which one is the #1 Bugaboo compared to the #2 Knifeblade. They sure look the same but are 1/32” different. Both Knifeblades and Bugaboos have a slight taper to the piton blade.
In 1965 only one Knifeblade and one Bugaboo was offered. These new pitons are die cut so the piton eye has a more round shape to them. Many only have a Chouinard “C” stamp and no “USA” on them.
In 1966 Chouinard offered 5 different sizes of Bugaboos. These have the Chouinard “C” stamp on them with “USA”
In 1967 Chouinard offered only 2 sizes of knifeblades and 2 sizes of Bugaboos. These 1967 versions are the most difficult to figure out between the 1966 set and 1967 set. The are almost completely the same except the 1966 version the hammer end of the pitons were flat. The 1967 version the hammer end has a slight curve to them.
In 1971 Chouinard redesigned the Knifeblades and Bugaboos where a second hole was added to them. 2 sizes of Knifeblades and 6 sizes of Bugaboos. The second hole allowed the pitons to be placed in a vertical or horizontal position since there were two options for the carabiner to be clipped to the pitons.
Chouinard Knife Blades shown in the 1960 Dolt Hut catalog
Chouinard Vertical Knife Blade Many are prototypes c.1959 YC Collection
This shows that the newer Bugaboo shape was created and then the second hole was added to the Bugaboos. So sometime fall/winter 1970 there may have been a bunch of sets of six size bugaboos created that do not have a second hole, but do have the newer bugaboo shape.