P67-ii Tight Bayonet Mount

[mtjade2007]

My p67-ii's bayonet mount is fairly tight to mount and unmount all my P67 lenses. I don't feel comfortable if it continues to be like that for long term. Is it supposed to be like that or is there an official way to lubricate it? None of my 35 mm gears has this issue. All my Contax cameras and lenses mount easily but not loose. I really don't think the P67 bayonet mount needs to be that tight. Thanks for any suggestions. Merry Christmas.

 

[shutterfinger]

There is a factory service manual for the Pentax 67II if this is what you are asking about.
https://learncamerarepair.com/downloads/pdf/Pentax-67-II-service.pdf
The parts breakdown is on pdf page 75, fig 3. The bayonet is a complex assembly. I would check for a loose screw, a bur on the ring, or a bent ring by placing a straight edge across the bayonet opening and verify the bayonet ring is equal distance from the edges of the body.

 

[mtjade2007]

Thank you for the suggestion. I don't think my p67-ii is broken and needs a repair. All my lenses will mount and dismount except it is kind of tight. I believe it just needs some lubrication. I am aware that I need to do it the right way or a wrong lubricant can cause a mess to the camera or the lens. Maybe I have not used the camera frequent enough. Maybe over time with the use of the camera it will become more reasonable.

 

[Alan9940]

I had a P67 for many years, sold it and replaced with the P67 II and both bodies had/have this "tightness" when mounting/dismounting a lens. I own 5 primes and 2 zooms and they're all the same. IMO, there is nothing wrong with your camera and I would strongly advise to keep any lubricant away from the lens mount.

 

[mtjade2007]

That's great to hear. Thanks for the information. I bought my p67-ii in 2002 and the bayonet mount was tight to begin with. Maybe I am getting old but the mount isn't getting looser or at least easier for me. Glad to hear it is the way it is supposed to be. I don't think something has gone wrong either. Just wondered if there is any maintenance such as a lub to the mount needs to be done. The pandemic has caused the camera very little use. That's maybe why I felt the tightness of the mount when I took it out to give it some exercise recently. Thanks again for your experience of it. Happy holidays.

 

[shutterfinger]

While I do not recommend the use of any lubricant on camera mounts this dry film teflon is the only one I would use.
https://www.amazon.com/DuPont-Non-S...=1640565576&sprefix=teflon+dry,aps,150&sr=8-3
Apply with a swab and allow to dry completely before attaching a lens.

 

[btaylor]

I have found “nose grease” often works to ease two flat metal surfaces together. And it’s always available…

 

[AgX]

At average lenses for MF SLRs yield more leverage on the mount than resp. lenss for 35mm cameras. For a part this is countered by the larger diameter of the mount.

A resulting higher leverage effect must be countered with a higher force of the bayonet springs. [Such springs are typical with bayonet mounts, though there are springless mounts, e.g. FD breech lock.]
A higher spring force then will result in higher friction.

 

[mtjade2007]

I tried again to mount all my 9 primes today and found that I probably don't need to worry about it. The mount is tight but not really excessively tight. My fingers are no longer as young as 20 years ago when I bought the camera. I did notice a fact that I am no longer able to remove can food caps easily which had surprised me in recent years. I might give the teflon dry lube a try as sutterfinger suggested if I really feel it necessary. I made a conclusion that although the mount is tight but it is reasonable still. I will leave it alone for now. Thanks for all the suggestions.

By the way, I have a cheap 2x tele coverters for p67. I can apply tiny amount of dry lube to the mount of this lens and mount it to the camera. This will transfer some lube to the mount base of the camera. This hopefully will not mess up the camera mount with excessive lube as a result. Will see if I eventually feel it necessary to do it.