In an old shed. Total length 7&3/4ths, tip width 1/8th. Stamped on the shaft is 405 osborne. Anybody have an idea? thanks
Bruce 

Hi Bruce, follow the link below to a collection of Osborne catalogs. Should keep you out of trouble for an hour or two.

https://archive.org/details/internationaltoolcataloglibrary?and%5B%5D=osborne&sin=

Mike

Probably a "caning chisel," used in removing the cane from seats of the type that use a cane spline to retain the woven cane in a groove around the seat opening - similar concept to the spline that retains window screen in modern aluminum-frame window screens.

Caning chisel it is. Thanks
Bruce