Cornwell SD-100....what is it for?

[Zrxrunner]

Found this at an estate sale, and no idea what its for? Google dont help either. Normal screwdriver handle. However...the square shank is spring loaded and retracts into the handle. Tip is 5/8" wide, and looks kind of like some of the old valve lapping adaptors i've seen. Aybe light duty spanner tool?

 

[RTM]

Tappet adjusting screwdriver P56 lower right.

Cornwell Quality Tools : Catalog A-56 : Cornwell Quality Tools Co. : Free Download, Borrow, and Streaming : Internet Archive

132 p., illus., 17.0 cm, trade catalog

archive.org

 

[Zrxrunner]

Holy ****, that was fast RTM! Catalog master! Thanks!!

 

[RTM]

googling "sd-100" cornwall, looking in google books