Quote by emileverbunt View Post
pic's two and three show, to my mind, the the top of a Dutch hand grenade. I think the "Scherpe nr.1" of WW2 vintage.

The neck of the grenade should show a coarse thread where the cap has been screwed on and off for arming and throwing.
Look here:

Google Afbeeldingen resultaat voor http://www.freewebs.com/nederlandinwo2/eihandgranaat3.jpg

Thanks for the link Emile. Seems to be the black version of the Dutch 'Ei' handgrenade.