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nikon lens repair stuck phillips screws

claude batmanghelidj , Feb 23, 2004; 08:36 a.m.

I have found that if I open up a nikkor lens that has stiff focusing and apply a little lighter fluid to the focusing grease it loosens it up. I bought a really nice 105mm micro that is really stiff, unfortunately the phillips screws on the lens mount just will not give and I cannot open it up! I don't want to strip the heads, any suggestions?


Zack Lau , Feb 23, 2004; 10:15 a.m.

Japanese generally use Cross Point instead of Phillips--the proper screwdriver may help.

Neal Shields , Feb 23, 2004; 10:21 a.m.

"Striving to better, oft we mar what 's well". Shakespeare King Lear.

First they may not be phillips. The Japanese camera makers have a special type of cross point. If your screwdriver doesn't seat perfectly leave it alone or order the correct tool.

If you think you have the right screwdriver, nest the lens in a sandbag or vice and while pressing down on the screwdriver and exerting twisting force, have someone else GENTLY tap the end of the screwdriver.

David H. Hartman , Feb 23, 2004; 10:24 a.m.

As long as you understand that I have NOOOOOO responsibility for what you do to this poor lens I’ll tell you how to get inside.

The screws are locked with a white thread lock. You can loosen them with MEK, Acetone or as a last ditch effort with a micro butane soldering iron. The way to correctly apply the MEK or Acetone is with a small, sharp pair of professional tweezers. The fluid is held by surface tension and released directly in contact with the screw heads. It takes several minutes to work. You will reapply the fluid perhaps three times. Failing this you can just torque the heads off the screws and make the lens useless.

Your best bet is to don Sackcloth and Ashes and take the lens to a Qualified Camera Repair Shop and lay prostrate on the floor begging for mercy. If you can’t find genuine sackcloth just buy some burlap cloth at an art supply.

Please don’t set the lens on fire. Many fine guitars met their fate in the ‘60s in ritual destruction and I would hate to see a trend such as this started on the lenses I love.

Scott Warn , Feb 23, 2004; 06:36 p.m.

I have recently acquired several classic Non AI nikkors and have upgraded them with the Nikon conversion kits. To do this requires removing exactly those screws that you are fighting and there is a very easy way to do this.

Pre heat your oven to 130 degrees using an accurate oven thermometer. Remember, 130 degrees and not any hotter than 140! Most ovens on warm will maintain these tempertures. Then, set the aperture to the minimum opening and put the lens in the oven for about 30-45 minutes until its toasty. Put on some leather gloves and while the lens is still warm, break the screws loose. The screws will still be somewhat stiff but if you have a well fitted screwdriver they will break loose.

I am sure that this advice will have many thinking that I am quite nut's but let me explain my reasoning. Nikon designs and tests their products at both extreme low and high tempertures. 130 degrees is at the low end of what a camera or lens stored in a hot car during the summer will be exposed to and I am confident that Nikon is aware of this. Now, I do agree it is not a good idea to expose a lens to these temps repeatedly. That is just asking for grease bleeds onto the diaphragms. However a one time exposure to this heat for a short period of time should be fairly safe. I cannot guarantee that you won't end up with grease on you aperture, but the three lenses that I have done this to, all are fine, no sticky diaphrams at all.

I did make sure to set the aperture to the minimum before heating the lenses and would recomend that you do the same. Setting the aperture to the smallest opening will uncover the blades to the fullest extent. By doing this you are reducing the capillary pathways to the minimum possible. Grease bleeds onto the aperture blades during a hot soak due to capillary action and minimizing capillary surface will help prevent the grease from bleeding.

claude batmanghelidj , Feb 23, 2004; 07:07 p.m.

Wow, thanks for all the advice. So, what is the difference between a cross and a phillips? I bought my miniature screw drivers at the Hyaku Yen store, (Japanese store where everything is 100 yen). They are decent, but are they not the right tools for the job? I am mystified. As for the oven, well, like most Japanese (which I am not, but I live here) I have no oven, so even if I had the nerves of steel to bake my lens, I could not. Are you sure they seal those screws in?

It's a 105 micro that is optically flawless, and I paid next to nothing for it, so maybe just leave well enough alone and live with the stiff focus? I did drop lighter fluid through the space under the focusing ring and twist it, which did a greatjob loosening up the focus, but the next day it is almost as bad as it was in the store when I bought it as a "junk" lens.

David H. Hartman , Feb 24, 2004; 03:51 a.m.

"I am sure that this advice will have many thinking that I am quite nut's but..." --Scott Warn

Scott, why heat the whole lens and risk problems with lube contamination of the aperture blades when it can be done in less time by doing it the way camera repairmen and women do it? If heat must be used it need only be applied to the screws themselves. The screws are magnetic steel and will transfer the heat very rapidly directly to the thread lock. I recommend focusing the lens to its close focus distance as this will help protect the rear element on many lenses.

The procedure I recommend is far safer for the lens and just as effective. MEK, is not used by some camera repairmen as constant exposure is not health for the brain. For a person who does this only occasionally there is no need for concern other than reasonable ventilation. There are special dispensers with stainless steel caps and a pump inside. A pair of tweezers or Q-Tip is simply pressed in the center, the fluid is pumped up and it’s then transferred to it’s indented target, in this case tweezers to the screws on the bayonet. Like the screwdrivers below this fluid dispensers are available from camera repair supply companies.

The precision screw drivers I use are manufactured by Canon as I recall. They were a gift from my camera repairman friend. I quite certain they were purchased from MicroTools. When using these screwdrivers it’s very convenient to pass them over a strong magnet several times to magnetize the screw driver. In this way the screws can easily be picked up when working.

For losening up a stiff helicoid Lyon Oil is applied in very small amounts with a 1cc suringe, then worked in well. Lyon Oil is available at MicroTools. If the helicoid is short on grease a *light* helical dampening grease is used.



Scott Warn , Feb 24, 2004; 06:32 p.m.

Dave, I recomended the oven method for one very simple reason. Almost everyone has an oven and every oven that I have ever owned would hold about 130 degrees when set on warm. I don't think I would do this with an AF lens, to many plastic parts in them but with the older all metal lenses I do think that it is a safe method. The microtorch that you recomend is something that not everyone owns and you do have to be pretty careful not to overheat the screw or local area. Probably the safest answer is to use MEK, but it is probably toxic and I think it would be best to use MEK out of doors.

I have also had the aperture rings off all my AF lenses (added rabbit ears to them) but for some reason the locktight could be broken loose without any aids, such as heat or MEK. Maybe it's age that makes the screws on the older lenses so stiff.

I have always used a precision screwdriver set from Sears. They fit the screws quite well and the set has a wide selection of sizes.

David K , Apr 15, 2009; 05:28 p.m.

How about a brief touch of a small soldering iron to the screw head, checking periodically as the screw warms up? When I was repairing violin bows it was amazing what a little heat would do to release a seized screw. Good luck...

Kyoshi Becker , Feb 19, 2011; 03:50 p.m.

Will the bake solution work with a nikon em body? I'm taking the camera body apart for fun and could not get any of the screws off the lens mount(No worries I have plenty of film cameras I shoot with).

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