Text and Photos by Bob Warkentin

The Coin Slot of the Battery Cap vs. the Proper Tool
The Three Areas of the "Flip-Flop" Damages | Damage #1 | Damage #2 | Damage #3
Where is the Battery Compartment in the Camera?
Proper Installation Techniques

I have to ask: who in their right mind would waste their time to fully study the mechanics (and damages) of screwing in a battery cap into a Nikonos camera? Well, I hope everyone will after reading this article.

The reason is that I constantly see camera after camera with a broken plastic battery compartment, pieces of which can fall and either jam or damage internal functions like the shutter assembly, and/or major permanent gouges put into the camera's main outer ($250.00+) water tight casing resulting in flooding, and other problems costing you good money. And when do these problems begin? From day one of ownership!

This seemingly mundane human operation of installing the battery cap into the Nikonos camera is always done wrong, at least in my opinion.

Because screwing in a battery cap seems so simple and straight forward a human operation, people typically resigned themselves to the ever present battle of fighting the Nikonos battery cap "flip-flop" during installation thinking it's just a normal factor of Nikonos life and certainly not something that you could be doing wrong! One merely sees the "COIN SLOT" in the bottom of the battery cap, reaches into their pocket for any coin, foreign or US, and begins unscrewing from, or screwing in, the cap of the camera. As long as you can finally get the cap into or out of the camera, who cares what the COIN SLOT finally looks like (photo 1). And if the batteries turn on the electronics of the camera this time, and the camera didn't flood this time, and you got some pictures, what could be wrong with the way you put in the batteries?

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The Coin Slot of the Battery Cap vs. the Proper Tool

Do the edges of your battery cap's coin slot now show signs of battle scars (like those in the 4 caps of photo 1)? Then it is for certain that you have been using a wrong size coin, and battling the battery cap "flip-flop" when installing the cap into the camera's battery compartment (as well as over-tightening the cap and/or leaving it installed to corrode in the camera without removing it every day for cleaning; but these are other human mistakes for later discussion).

Battery cap coin slot
Photo 1

When selecting a coin to use for a Nikonos, first, and most importantly, always keep this concept in mind: use only a proper sized tool (coin) for the properly required size job! I recommend using ONLY a US nickel: it's the proper tool for the proper job!

Photo 2

Many nickels have NOT been stamped flatly; that is, the edge of the nickel is THINNER on one side and THICKER on the other. Since the edge of the coin is "roundly" graduated from thin to thick, you will be able to install the coin into the battery cap's slot and roll the coin until the coin completely, firmly and perpendicularly LOCKS into the entire slot. In fact, you will now be able to pick up the cap, full of batteries, and wherever you move the nickel, so goes the battery cap full of batteries (photo 2)! Now, you've got CAP CONTROL!

You may be thinking: "What's the big deal with the size/thickness of the coin? With needing complete cap control? With battery cap "flip-flop"? If the battery cap's coin slot finally gets so messed up that every coin you now use, nickels included, always slips out of the slot when you remove/install the cap, you can just buy another cap; they can't be that much?" Obviously, I wouldn't be writing an article about preventing you from messing up a $10.00 user-replaceable cap if there wasn't more to it. And believe me, there are many serious damages going on within the camera when the cap goes "flip-flop" because you have not got control of the cap!

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The Three Areas of "Flip-Flop" Damages

Obviously, any coin thinner than a nickel (like a US quarter, dime, or penny or a 100 Yen coin) can not provide you with the control needed to safely install a Nikonos battery cap. So, when your thin coin "flip-flops" in the coin slot, you have lost complete control of WHERE your battery cap is going. The "flip-flop" of your thin coin unfortunately causes the battery cap to also flip-flop inside the hole of the camera's casing. Results: three areas of serious damage costing you anywhere from $150.00 to having to buy another camera!

Damage #1

First, let's study the metal battery cap and how it is designed. In photo 3, notice that the O-ring channel has been cut out of the solid metal base. Therefore, on either side of the O-ring channel are metal walls and metal edges.

Note: All O-ring seats, regardless whether they are found in a Nikonos or a pipe line, require a total of four walls for proper seating/enclosure of the O-ring. Also, the four walls must have a minimum of clearance between them where pressures are involved. For a Nikonos camera, we typically call the three walls an "O-ring channel"; for the fourth wall, most people don't even realize it exists and therefore don't give it a catchy name. Better try on this name in your vocabulary from now on: the camera's MAIN OUTER CASING, whose cost to replace is over $250.00!

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Photo 3

Next, notice that the edge nearest to the cap's threads has a 90 degree shoulder (remember, it's metal!). As the cap goes into the hole of the damage can occur. There is just enough clearance to allow the two pieces (cap and camera casing) to be installed together while compressing the O-ring for water tight use.

Watertight seal
Photo 4

But, when the cap "flip-flops" sideways as you try to screw in the cap, the 90 degree edge is no longer kept parallel to the casing's fourth wall. Your sideways installation now causes the 90 degree edge to cut into the fourth wall of the camera's MAIN OUTER CASING. And, as you continue to rotate (screw in) the metal cap, this 90 degree edge cuts barber-pole circular gouges into the casing's wall (photo 5). Unfortunately, you are not just removing paint. You are permanently damaging the casing's metal wall and the camera's water tight seal-ability. It could flood!

Casing wall
Photo 5

Nickel plated casing
Photo 6

Oh! You've got the style of casing with that nickel plated thing around the hole. Well, humans can still screw them up as well (photo 6). And if too damaged, then the whole outer casing must be replaced just to get a "new", smooth hole. Cost of casing: $250 +!

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Damage #2

Uneven wearing of the threads or cross-threading. While I think the latter speaks for itself, let me address the former a little further. Notice in photo 7 that the threads are now a golden (brassy) color due to being worn, and lots of fine brass filings due to being cross threaded. In fact the outer most thread, the first thread seen by the battery cap, is the most worn; the next ones are worn progressively less in intensity which accounts for the appearance of wear in a "funneling" configuration.

Worn threads
Photo 7

I know somebody out there has cussed the fact that they can't unscrew the battery cap far enough out of the camera's hole as they once used to so that they can grab it with their fingernail. If you are one of those, better check the color of your threads. How many gold ones do you have? And, you better have the "funneled" ring replaced. It ain't cheap, but it is cheaper than a flood or other damages you will cause if you do not have it serviced!

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Damage #3

The black plastic battery compartment has only a specific capacity: it holds only the volume of a tall battery (or 2 small ones) when installed PERPENDICULARLY! But, as your metal cap (loaded with metal batteries!) flip-flops in the battery hole of the camera because you are using an improper tool (coin), not only is the metal battery cap being SCREWED in somewhat sideways but also the metal batteries are being FORCED into the plastic battery compartment somewhat sideways (diagonally). Well, in case you forgot your high school geometry, diagonal distances (height) are always greater than perpendicular distances (height). Therefore, your flip-flop battle with the battery cap (caused by your loss of cap control from not using the PROPER TOOL!) causes the batteries to go diagonally into and up against the plastic battery compartment causing it to be broken.

Results are many! Loss of battery contact; no electronic camera operations; and, pieces of the broken plastic falling into the shutter's gears blocking or breaking shutter operations. Replacing the broken plastic compartment isn't cheap, much less the labor involved with having to take apart all of the camera parts just looking for all small pieces of broken plastic. But if the shutter is also damaged, you will really learn the value of a nickel!

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Where is the Battery Compartment in the Camera?

Battery compartment
Photo 8

Way, way down inside the camera. In fact, after the shutter is put into the camera during assembly, the next thing usually is mounting the battery compartment! For repair or replacement of either the threaded ring or the plastic compartment, this means removing the entire inner guts from the camera's casing, then undoing all of the electronics and nearly 50% of the mechanical parts before you can get to it. After replacement, everything has to be put back together, calibrated, all O-ring cleaned, and then pressure tested before the job is done. Lots of time, lots of labor, and lots of nickels!

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Proper Installation Techniques

I guess you now know the value of a nickel. Here is how you put it to work for you:

  1. Roll the nickel into the battery cap's coin slot until it locks to the coin slot. (If yours doesn't, either get another correct nickel or get yourself a new battery cap.)
  2. Holding the nickel perpendicular to the hole of the camera, insert the cap straight up and down.
  3. Once in the hole, begin screwing COUNTERCLOCKWISE while putting some inward pressure onto the coin. Continue this combined counter clockwise rotation/inward pressure until you hear a "click" sound (you may have to rotate anywhere from 1 degree to 359 degrees until the "click" sound is heard). Remember, keep everything perpendicular!
  4. Once the click is heard, you may be surprised to know that you have properly aligned the starting thread of the cap directly in line with the starting thread of the compartment's ring!
  5. Now, begin screwing in the cap CLOCKWISE. It should screw in as smooth and easy as cutting through butter with a hot knife. But, still use caution during your first few times of practice/self teaching. You may not have heard the click, went too far past the click, or still held the cap sideways and never heard the click. And, excited that you heard the click, you may tilt the nickel after all and still cause the cap to go in sideways. Just begin cautiously to rotate clockwise only about half a turn feeling as you go; smooth feeling, screw it all the way. If not, start all over again...PERPENDICULARLY this time!

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  1. Take your battery cap with you to the bank and buy several rolls of nickels. When you find your PROPER TOOL nickel for the proper job, better find at least one more.
  2. Putting a battery cap into a Nikonos ain't hard. Rotate counter clockwise first until you hear the click; then clockwise!
  3. Remember your high school geometry terms: perpendicular, diagonal distances, parallel distances, capacity and volume. Don't over fill the black plastic compartment.
  4. The "gold" color you see on the threads of the battery compartment in the camera and the battery cap doesn't mean you discovered hidden treasure, it means it will cost you your hidden treasure to have these damages fixed.

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Reprinted with permission from Bob Warkentin's Southern Nikonos Service Center, Inc.
9459 Kempwood, Houston, TX 77080 • 713/462-5436