I have a cheap set of HF needle files that I have about worn out. I want to replace them, because I do use them often. I'm wondering if the diamond files are better than the steel ones. Are they good for wood work or more for medal? I know nothing about them other than I use them a lot. Maybe the HF ones are good enough, but if there is an upgrade that is worth a little extra money I'd be willing to spring for it.