Gear Talk > What the Nerds Do
Ai Conversion - Getting the mount off
Roland Vink:
I have a couple of K (New Nikkor) lenses and managed to obtain original AI conversion rings for them. Yesterday I tried to install them. I borrowed a solder iron to heat the screws (to soften the loctite) but has no success, they wouldn't budge. I only have a regular set of small screwdrivers - probably Phillips (not JIS) and the screwdrivers have a narrow handle so I wasn't able to apply much torque. Any tips on getting them out? I probably should invest in some JIS screwdrivers - what would you recommend? Thanks.
(not sure if this belongs in the "nerds" section ?)
Bjørn Rørslett:
Maintenance or modification of Nikkors is suitable for the "Nerds" board.
You definitively need a set of JIS screw drivers. Standard Philips drivers can easily rip or damage the screw heads when the screws are tight. Use only JIS drivers and press hard, then first try to slightly tighten the screw further before you flick the driver in the opposite direction.
You might want to soak the mount by a solvent such as hexane overnight before next try, even with the proper JIS tools.
Microtools.com is a good source for JIS screw drivers.
Early Nikkors can really be a tough challenge. Often the loctite bonding has almost petrified after decades. If soaking doesn't suffice, try putting the lens in the deep freezer over night, then immediately apply heating with the tip of a narrow solder iron.
Last resort is using a small hammer to make sure the screw driver is well and truly stuck in the slots, then apply lateral torque. Or use a narrow drill bit 1-1.5 mm in a solid chuck and drill out the screw. Be warned this should be done with the drill in a jig not hand-holding it, as the screws can be *very* hard and unless you do this carefully, the drill bit can easily skid off the target and cause a lot of damage in the mount itself.
Øivind Tøien:
My experience with the soldering iron is that it may take lots of repeats varying heating time, with immediate wiggling back and forth of the screwdriver (not necessarily with maximum force, but with high downwards pressure) at each try. The keyword is repeated thermal expansion/contraction. A cold pack might be useful to cool things down between repeats. So there might be hope even if there is no initial success. And yes, definitely use a JIS driver.
Erik Lund:
Most important is to; Have a stable table top to work on, remove lens hood filters etc, select a screwdriver that fits 100% into the screw, stand up so you have your uppere body weigth over the lens, unscrew the screws...
Øivind Tøien:
Erik, which JIS driver # do you find fits best into the mount screws?
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