How to mount and dismount M42 adapter

There are different versions of genuine adapter with different wordings that I have seen. All genuine adapters go without an extra tool in dismounting, and when new, they come with a green packet
  • "Asahi Pentax" on top and "Japan" on bottom
  • "Pentax" on top and "Japan" on bottom"
  • "Body Mount P/K" followed by "Japan" on top
Genuine Pentax M42 to K adapter

Genuine Pentax M42 to K adapter

Genuine Pentax M42 to K adapter
You can reference the dismounting/mounting instruction in this link

I personally use thumb and index fingers to do the dismounting instead of using pen as in Pentax instruction.

  • For genuine adapter, there is no reason to remove the locking plate. The locking spring plate has to be in place to secure the lens

  • There have been confusion with other users who remove the spring locking plate on 3rd party adapters as the screw and spring plates are easily worn causing jamming of adapter in K mount bodies. Those conversions should only be done on 3rd party adapters.

  • You only perform K mount conversion on 3rd party adapters as this genuine adapter should be used according to instruction, which is always mounting the adapter on body.

Rough Instructions

  • Precaution step is to have your camera resting on base, don't lay your camera on its back as adapter can fall into the mirror chamber during mounting and dismounting steps

  • I use thumb and index finger to hold the adapter, line up flange onto three open areas in K mount

  • on mounting, remember to tuck the spring plate in and turn clockwise until you hear the click

  • on dismounting, find the open hole and tuck the spring plate towards center and turn adapter anti-clockwise. Without tucking the spring plate, the adapter is locked in place in the K mount body


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