How to avoid stripping Screws when disassembling a Camera

Discussion in 'Camera Building, Repairs & Modification' started by TerryM, Sep 1, 2010.

  1. TerryM

    TerryM Member

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    I want to share with you three of my techniques to avoid stripping screw heads when opening up a camera. Firstly, what you need to do is FREEZE the screw head with ICE. To prevent the camera from getting wet, just place the ice cube into a plastic sandwich bag, and push that against the screw head for about 30 seconds. Freezing will make the metal harder, and less likely to strip. In addition to making the screw harder, freezing also causes the metal to shrink a bit which makes it easier to unscrew. You will need to keep re-freezing it every 30 seconds until the screw comes loose.

    My second technique when unscrewing a stiff screw is to not apply constant turning / torque. Constant turning is what will lead to the screw head stripping. When unscrewing a stiff screw, you need to use QUICK JOLTS. You accomplish these jolts by only very briefly applying the turning / torque with the screwdriver for only a fraction of a second at a time, and then you quickly let your hand loose on the screwdriver handle to stop the turning. These brief turning jolts, combined with freezing, will eventually jar the screw loose without stripping the head. For my third technique, it is also necessary to push the screwdriver VERY HARD into the screw head in order to prevent it from slipping. The screwdriver slipping is what wears down and strips the screw head, but hard pressure avoids this.

    I want to make a comment on those tiny screws which hold the lens dials onto the lens. Those tiny lens dial screws are likely headless, and only consist of the cylindrical screw body with a groove on the end for the screwdriver. These screws are also likely only threaded into the dial itself, and only apply "pressure" onto the inner lens case to hold the dial in place. Those lens dial screws are also probably glued into place to keep them from coming loose -- so you need to pick away the glue before unscrewing them. After screwing them back into place, you can use a toothpick to apply a small amount of paper glue on the end which will keep them tightly in place.

    There might be some screws hidden behind labels -- so you may need to carefully pry away some labels. Use a piece of masking tape to securely hold the screws in the order you remove them -- they're tiny and you don't want to lose any of them. These techniques worked with 100% success for me when removing all necessary screws to open up my Super8 camera, and they will also work for you. Good luck! :smile:
     
  2. mike c

    mike c Subscriber

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    Good advice.
     
  3. nick mulder

    nick mulder Member

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    Great advice, until you meet a reverse thread and make it even worse ...

    Best tactic is to know how to spot likely spots that they'd be used before you go tightening them - where the action of the piece is such that the net forces try to unscrew the bolt (?)
     
  4. AgX

    AgX Member

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    My advice would be to have a great assortment of screwdrivers, and not to hesitate to grind a blade to the best fit.

    Terry,
    Have yo thought about using `cold spray´.
     
  5. TerryM

    TerryM Member

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    I knew that somebody was going to bring up the unlikely scenario of a reverse thread. :laugh: :laugh: :laugh: Have you ever actually encountered a reverse-threaded screw on a camera? :D

    Note to novices: you turn the screwdriver to the LEFT (counter-clockwise) to unscrew it. I don't think you'll come across a reverse thread.

    Yes, definitely make sure to have the necessary tiny screwdrivers right down to 1mm. Those tiny screwdrivers are made with hardened metal. Don't try to use too large a screwdriver! The lens dial screws are likely 1mm.

    I've not heard of cold spray. Is that a lubricant? With freezing I didn't encounter any problems. :cool:
     
  6. nick mulder

    nick mulder Member

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    The Mamiya RZ67 ProII back uses reverse threads :tongue: (assuming we're talking metal thread/bolts and plastic screws also ?)

    The cold spray is often found in electronics stores - used for instance in keeping electronic parts cool whilst working with heat nearby (soldering etc...)

    [​IMG]
     
  7. AgX

    AgX Member

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    1mm is waaay too much tolerance, even for "around the house" screws!


    Cold Sprays are organic liquids with a very low boiling temerature. They are made by compressing gases of that substance in small spray cans. Sprayed on a surface they evaporate and yield evaporation cold. They are used in the technical and medical world.
    Most, if not all are flammable.
     
  8. Marco B

    Marco B Member

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    I think I have seen that stuff being used when they needed to replace my water meter in my house two years ago. The guy had a can with a kind of wrap attached to it, that was wrapped around the metal pipe to freeze the water inside it before cutting it to replace the water meter...

    Very handy...
     
  9. steelneck

    steelneck Member

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    It could also be carbonate, like in some fire extinguishers or for making soda water. Ice from this evaporates at -78 celcius.
     
  10. AgX

    AgX Member

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    Yes, but CO2 needs stronger containers, as it will liquify under much higher pressure.
    The soda making capsules contain CO2 gas not the liquid.


    Back to sticking screws.
    Ideally the cold is applied to the screw only, as with that (deep frozen) ice cube.
    Simply spraying the screw head (especially in sunk heads) would be less effective than applying the liquid that way that it won't reach the body where the screw sits in.

    At least I guess so...
    I mean: will a hole that sits in a much larger body shrink or extend, when cold is just applied to that hole??
     
    Last edited by a moderator: Sep 2, 2010
  11. Jeff L

    Jeff L Subscriber

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    >>>Note to novices: you turn the screwdriver to the LEFT (counter-clockwise) to unscrew it. <<<


    Ah yes. Lefty loosey - righty tighty.
    Advice from my sarcastic airplane mechanic friend.
     
  12. Sethasaurus

    Sethasaurus Member

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    I've found, while working on a lot of older cameras with slotted screws - the screw slot is significantly thinner than the screwdriver you might want to use.

    That is - the screw head may be e.g. 3mm diameter and you might pull out a 3mm slot-head screwdriver but it won't fit. Then you get tempted to step down to a smaller size driver which fits in the slot. This often results in making the top of the screw look ugly when it slips because you can't apply enough torque to move it.
    It's nice to have precision-made, lifetime-warranty tools that will always work (I like Snap-On tools), but it is also easy to get hold of a few decent screwdrivers for next to nothing and shape them to your needs.

    Another tip for stuck screws is to place the driver in the slot (or cross or hex, etc) and give it a firm whack. That often helps to break up any gunk or glue that may be making it stick. Metal jeweller's screwdrivers can handle this but you may tend to mangle the plastic ones or push the shaft into the handle.

    Swearing and threatening it sometimes helps too :wink:
     
  13. John Koehrer

    John Koehrer Subscriber

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    You will be laughing out of the other side of your mouth when you hit one.
    Pentax has used them on the Spotmatic series. They also changed the damn things to RH threads toward the end of the Spotmatic production. I recollect a lefty on the OM cameras, but that's a recollection, not a memory.
    The best advice would be to use a screwdriver that is a correct fit, snug and the diameter of the screw head.

    The headless screws you refer to are called "set screws"
     
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  15. nick mulder

    nick mulder Member

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    reverse threads:

    lefty righty, tighty strippy


    The cold spray thing - I often worked the inverse of that and heated up the outside (the 'nut') - works just as well (or not) as the cold on the bolt gag
     
  16. TerryM

    TerryM Member

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    I don't know who came up with the stupid idea of a reverse-threaded screw, but that person should be SHOT! :mad: The reverse thread is a much dumber idea than "metric" threads! I fully support the metric system, but not for threads. :blink:

    I was referring to the diameter of the screwdriver. I had bought precision screwdrivers -- going down to 1mm -- before attempting to open the camera. The lens needed 1mm.

    Try my three techniques the next time you attempt to open a camera. You'll see how successful they'll be. :wink:

    In the case of nuts and bolts, just use an adjustable wrench, and make sure it fits extremely tightly around the nut. Then just "tap" the end of the wrench handle with a hammer to jar the nut loose. This worked successfully for me even with those delicate aluminum "flare nuts" which hold the brake lines on your car. It beat spending $8 bucks to buy a special flare nut wrench. :D
     
  17. resummerfield

    resummerfield Subscriber

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    Put a small dab of valve grinding compound (a very gritty compound) on the screwdriver tip before mating to the screw and attempting to remove. The grit will bind the screwdriver to the screw, and often will prevent the screwdriver from slipping on the screw head.
     
  18. bblhed

    bblhed Member

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    1mm is .039 inches, the thickness of a match paper match, that is plenty of gap. :whistling: Oh, we want a tight fit.

    I'm sure they meant 0.1mm it was just a misplaced decimal.
     
  19. nick mulder

    nick mulder Member

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    reverse threads are useful ...

    essential even in some applications - the ones they are used for :wink:
     
  20. andrewkirkby

    andrewkirkby Member

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    The key is to use a high quality screwdriver that fits the screw head perfectly. Too big and you strip the screw head, too small and you can't get the torque required to release the screw and probably will strip the head as well.

    The screws used in most consumer electronics are of very poor quality. While working at Canon, it was common procedure to replace removed screws with new ones, especially within lenses.
     
  21. Poisson Du Jour

    Poisson Du Jour Member

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    Jeweller's screwdrivers with adjustable torque, some of which come in magnetised form, would be a wise investment; as AndrewK said, consumer electronics stores issues have lousy products which can break, damaging the screw, the equipment you are working on and possibly even cause injury. Screws that are difficult to remove and are removed eventually should be replaced. Canon replaced all the tiny screws in my EOS 5 about 10 years ago when it was in for major display driver and drive servicing.
     
  22. lxdude

    lxdude Member

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    How about wart remover, the type that freezes the wart? It's legal here. It has an end that looks like a Q-tip (cotton swab on a stick). It's applied directly to the wart. The same could be done with a screw, no doubt. One applicator might be enough if you do some in quick succession.
     
  23. andrewkirkby

    andrewkirkby Member

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    Wartner?

    I guess it would work, but it risks making the metal more fragile and prone to stripping (worst nightmare)
     
  24. Q.G.

    Q.G. Inactive

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    And so we have come full circle.
    Have a look at the OP, tip #1.
    :smile:
     
  25. sun of sand

    sun of sand Member

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    how would it work and yet make more susceptible to doing what it was supposed to not do

    what did i miss


    i shape the screwdriver to fit the head orif possible dremel the head deeper and wider
     
  26. andrewkirkby

    andrewkirkby Member

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    The product is known as Wartner, my comment was purely based on my own experience.