These are some photographs I found online. It has a triangular tip which creates a slit into the wood. Anybody know the name of it or something similar?
This looks like a custom punch
for nails and screws. To help ensure they don't walk when that are first being inserted. My only trepidation is that punches are normally cone pointed so that the hole has the same diameter. Quite possibly this is still a punch but for something other than nails or screws.
The main piece of metal I am not sure what it is yet but it's an unthreaded eye bolt, held to the main shaft with two nuts, which looks like it is there to help you hold the tool in place.
I am more curious where you found this image. Knowing what was being built might add more insight.
From doing a little research I found this photo linked to a Netherlands forum where a user was making a Claviporte / home made piano. After reading the post it seems that my suspicion about the V shape was right. It was being used to create recesses parallel to the grain in a board that was to be made for piano keys.
It is indeed a custom tool for a custom purpose. Post refers to the main shaft bolt as a keel bolt. The outer handle is used to ensure the angle an which the v faces. Using this tool across the grain is likely to damage the surrounding wood. Hence why the handle is present.