what skill would be right for using tools like wrenches, hammers, large screwdrivers, etc as weapons? Primitive?

I would go with Primitive in almost all cases, yes. Maybe some exceptions for wielding an arc welder or something like that?

edit: Although the correct Talent in DH2 is called Weapon Training (Low-Tech) not Weapon Training (Primitive).

Corebook, Table 5-8, page 159, "Improvised" in Low-Tech section.

3 hours ago, Jargal said:

Corebook, Table 5-8, page 159, "Improvised" in Low-Tech section.

Ah, I thought that there was something on that in the Core Rule Book but did not find it. Thanks!

Thanks.