600mm f4L mkii Lens hood screw....

[Mikehit]

This is a long shot but here goes.
The hood on the 600mm f4L is secured to the lens by a screw and wedge system. The wedge has become de-threaded which means it keeps dropping off when not attached to the lens. I am sure I will eventually lose it. Does anyone have any idea of the thread size/pitch so I can cobble a new one?

 

[neuroanatomist]

This is a long shot but here goes.
The hood on the 600mm f4L is secured to the lens by a screw and wedge system. The wedge has become de-threaded which means it keeps dropping off when not attached to the lens. I am sure I will eventually lose it. Does anyone have any idea of the thread size/pitch so I can cobble a new one?

Perhaps try contacting Canon and asking for a replacement part?

 

[Mikehit]

Thanks, Neuro.

I solved the problem - it is not a thread but a stud with a C-ring and the C-ring was missing. 10 bucks for a set of rings and it is operational (a bit cheaper than 500 for a new hood). Next problem is how to use the remaining 289 C-rings!