Found some old bashed Zenith Helios 44M lenses so wondered if I could use them on my Nikon gear..
Quick browsing left me with few findings.
1 . obviously you need an adapter.
2. other cameras can work with M42 lenses through adapters no problem, Nikon has deeper focal plane therefore once using adapter there is no room to get a lens deep enough to focus at infinity.
3. Its possible to focus at infinity if you purchase ridiculously( comparing to lens value) expensive adapter with reducing lens on its back. you get what you pay for...meaning, cheap one has poor quality lens which messes everything up, even expensive one isn't flawless .
4. I have read somewhere that because of focal plane, even if you get to focus to infinity, lens goes so deep that you would crush your mirror once firing.
I think nah....
So I have 3 Zenith Helios 58/2 44M (I bought 2 cameras on car-boot sale for 2 quid each for my 2 years old back then to keep him away from my gear). All of them survived 2 years with my kid (Gniotsja nie lamiotsja- common decryption for everything from CCCP meaning bending but not breaking).
Welcome to my Butcher style conversion.
Metal epoxy putty
Dremel tool with few attachments
2 drill bits
Nikon F lens mount ring (male) with screws.