What size screws for Canon ET-155 lens hood?

I have an 800L that is missing a tiny screw for the hood locking mechanism. Is there anywhere online that lists part numbers or give exact sizes of such screws? I think I might be ending up buying a hodgepodge of screws from Home Depot... but figured I'd ask first.

You can always call Canon and ask.

I have repaired a few "loose" hood locking mechanisms on Canon SuperTeles. I am not certain of the threads that they use but I have a number of screws for attaching Hi Fi cartridges to turntable arms and they fit perfectly. Take a visit to a local (good) Hi Fi shop and they will have something to fit.

I think it's something like M1.8x0.8. Google is your friend on this, search for schematic diagrams of the hood assembly, its what I did for my 300L

As far as I know, the Canon ET-155 hood is designed to protect the camera lens from snow, raindrops, or rays of light not involved in image formation. All this reduces the loss of contrast and improves the quality of your images.