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Completely agree about Nikon bayonet screws. Some of them are really bad. Some heating and well fitting screwdriver usually does the job but there is a stuck one more often than most of the others (ends with a screw drilled out).
No wonder that some factories can operate so efficiently:
View attachment 385402
Here I had over-tightened a screw head profile on a Nikkor 105/2.5 Ai. No method to remove the screw helped.
Drilling and unscrewing were not in my repertoire at the time, but Michael @forest bagger, a professional with a lot of experience in repairing Nikkor lenses, suspected that some Nikkor bayonets might have titanium screws. That makes it difficult.
I don't have any reasonable extractors for screws in M1.2 - M2.5 range. In most cases they're easily heated since they're small.
Come to think of it, all my screw drivers are cordless, but then one must consider that they all lack the battery power that the OP refers to.
Andreas - The reason Phillips screws are no longer used in numerous applications is because the bit does tend to slip and strip its fit in the process. It's not supposed to kick out. Over-tightening should be controlled in a different manner. Of course, a lot of this is related to the quality of screws and their alloys involved, along with the quality of the driver bits themselves. But that's why modifications like Posidrive and square drive arose, not to mention much more secure but slower inserting options like multi-point star drive inserts.
A cordless screwdriver, as shown, is far too powerful for sensitive photographic equipment. Your hands give you more control over the tool screwdriver, and don't put the item to be repaired in danger of damage.
The former Non-AI and AI Nikkor lenses had bayonet screws made of a non-magnetic metal that was relatively soft.That's the exact lens I had an issue with one screw. They're very soft.
View attachment 385402
Here I had over-tightened a screw head profile on a Nikkor 105/2.5 Ai. No method to remove the screw helped.
Drilling and unscrewing were not in my repertoire at the time, but Michael @forest bagger, a professional with a lot of experience in repairing Nikkor lenses, suspected that some Nikkor bayonets might have titanium screws. That makes it difficult.
JIS screws?
I'm struggling right now with this on a Canon FD 50/1.4 SSC mount. I have the correct JIS screwdriver, tried a soldering iron to get it hot, tried acetone but 2 of 3 won't budge. The one that came out shows no signs of loctite.
Yes, JIS, correct.
You could also try putting a small drop of WD-40 or similar on the thread for a few hours.
If there is no glue, this might help.
Andreas - The reason Phillips screws are no longer used in numerous applications is because the bit does tend to slip and strip its fit in the process. It's not supposed to kick out. Over-tightening should be controlled in a different manner. Of course, a lot of this is related to the quality of screws and their alloys involved, along with the quality of the driver bits themselves. But that's why modifications like Posidrive and square drive arose, not to mention much more secure but slower inserting options like multi-point star drive inserts.
Thank you. I have noticed recently that Phillips screws slip much more often then flathead or other screw heads and wondered why.
The flanks of the Phillips cross-head screws taper off towards the tip. The conical form facilitates inserting the tip of the screwdriver with the power-operated screwdrivers. In addition, an axial force is generated during tightening which pushes the screwdriver out of the screw. Originally, this effect was intentionally used as torque delimitation. But over time, it proved to be a disadvantage of the Phillips screws.
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