How to avoid stripping Screws when disassembling a Camera

Good advice.

 

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 (?)

 

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´.

 

The Mamiya RZ67 ProII back uses reverse threads (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...)

 

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.

 

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...

 

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

 

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??

 

>>>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.

 

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

 

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"

 

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

 

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.

 

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

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

 

reverse threads are useful ...

essential even in some applications - the ones they are used for

 

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.

 

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.

 

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.

 

Wartner?

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

 

And so we have come full circle.
Have a look at the OP, tip #1.

 

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

 

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