A handle does indeed exist as a noun in norwegian, and would be directly translated as "Et håndtak" but in tennis you would use the sister-noun "Et skaft".
Tusen takk for your very informative post. The link to the pictures of so many different types of "handles" was quite helpful.Handle is not a Norwegian noun. The English noun handle can often be translated to the Norwegian noun håndtak.
Here are some google images of handle:
In most cases I would use the word håndtak to describe what I see in these pictures, but on knives I would use the word skaft.