Pentax 67 seized screws

[norris47]

Hello dear people,
I am currently in trouble, trying to repair a pentax 67 aperture chain, as I realised that the screws holding the camera's front lens mount plate in place have seized. I tried adding a drop of wd40 and only 1 screw came loose. Do you have any suggestions for me?

Thank you

 

[shutterfinger]

Water Displacement #40 is not a good product to use in cameras.
Get some Acetone, apply around the screw heads with a cotton swab, wait 5 to 10 minutes, try the screw and apply the Acetone again if it does not come loose. The screws likely have a common threadlocker used in camera assembly on them that dissolves with Acetone.

 

[norris47]

Water Displacement #40 is not a good product to use in cameras.
Get some Acetone, apply around the screw heads with a cotton swab, wait 5 to 10 minutes, try the screw and apply the Acetone again if it does not come loose. The screws likely have a common threadlocker used in camera assembly on them that dissolves with Acetone.

Oh that is good to know. Luckily I only used WD40 in small amounts around the screw head. I shall try acetone and see how that goes.
Thank you

 

[ColdEye]

You can try a drop of TSI 321. Just a drop, I use this to remove/protect screws from salt water corroded screws on fishing reels I repair. Again just a drop is enough, let it settle for maybe 30mins.

https://www.blakdogtackle.com/product_info.php?products_id=1965

 

[shutterfinger]

The problem with WD40 is that it dries out in a few weeks and leaves a residue that will build up with repeated applications. The same is true for 3in1 oil. I have not tried other WD40 branded products.