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Modified San Diego Geocoin


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I'd like to show everyone a coin that I made. I took a 2005 San Diego Geocoin and modified it on a lathe so that it opens up from the back. I'm waiting for my order of 2008 Compass Rose coins, so I thought I would practice on this one. Actually, it takes two coins to make one of these. My intention is to make several of these from Compass Rose geocoins, and sell one or two.

 

Because geocoins are rather thick, you can actually hide useful stuff in them including notes, flash memory chips, etc. I just listed this one on ebay starting at 99 cents, click here.

 

I also have a link to a video that shows this exact coin in action here.

 

I'm selling this one mainly to see how much interest there is in something like this. Even though I'm using a lathe, it's still a slow process. This coin took about 3-4 hours to make. You have to go slow and careful or you damage it. Is this something geocachers would be interested in?

 

Dave

 

SDGeoCoin1.jpg

 

SDGeoCoin2.jpg

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Does it screw shut? Looks lik it's a slip on.

 

Can you take a single thicker coin and machine it to be a thinner screw shut coin? Yeah, I'm probably talking some very tight tolerances.

 

While i'm on that track what about a blank and you can screw the coin on either end. One coin and a cylender of varrying thickness with coin caps?

Can you do this to a non circular coin? Octagon for example?

 

Think you can machin a coin with glass or resin (like stained glass?)

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It's a nice gimmick. But at the cost of 2 coins + the labour to hollow them out and machine them to fit it would be insane to release in the wild.

Maybe as a Proxie!!! Use a couple of blanks then glue the photo of the coin you're copying to front and back with a list of tracking #s inside to other coins to discover. }:-)

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You're right, the coins slip together. When done right, they stay together very well and it takes a firm press in the right spot to pop it up.

 

I'm sure having the coins screw together would be possible, but I don't have that ability right now. That would require even more work than it does now!

 

The lathe tools can be used to machine plastic and I'm sure resin would be included. I'm not sure how it would go if a geocoin had plastic and metal sections. I'd have to experiment.

 

You can't machine non circular things with a lathe, but you could take an octagonal geocoin and machine a circular area in it, I suppose.

 

Dave

 

Does it screw shut? Looks lik it's a slip on.

 

Can you take a single thicker coin and machine it to be a thinner screw shut coin? Yeah, I'm probably talking some very tight tolerances.

 

While i'm on that track what about a blank and you can screw the coin on either end. One coin and a cylender of varrying thickness with coin caps?

Can you do this to a non circular coin? Octagon for example?

 

Think you can machin a coin with glass or resin (like stained glass?)

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Here are the pictures I took while making this coin.

 

I usually work on the inset piece first. The coin is in the chuck and ready to go:

 

SDGeoCoinlathe1.jpg

 

I remove a small amount of metal to make the surface flat, then mount it onto a piece of aluminum rod.

 

SDGeoCoinlathe2.jpg

 

Once mounted on the rod, I can remove metal from the outside of the coin.

 

SDGeoCoinlathe3.jpg

 

The coin is then removed from the rod, flipped over, and material is removed, thinning it down to .025-.019 inches. Note the strips of paper between the coin and the chuck jaws to keep from scratching the coin.

 

SDGeoCoinlathe4.jpg

 

Machining of the outer coin is next and is much easier. Metal is removed out to the rim and the inset piece is test fit. This is done over and over, removing .0005 inches at a time, until the fit is right.

 

SDGeoCoinlathe5.jpg

 

Received my 2008 Compass Rose geocoins today and am looking forward to torturing a few of those!

Dave

 

 

I'd like to show everyone a coin that I made. I took a 2005 San Diego Geocoin and modified it on a lathe so that it opens up from the back. I'm waiting for my order of 2008 Compass Rose coins, so I thought I would practice on this one. Actually, it takes two coins to make one of these. My intention is to make several of these from Compass Rose geocoins, and sell one or two.

 

Because geocoins are rather thick, you can actually hide useful stuff in them including notes, flash memory chips, etc. I just listed this one on ebay starting at 99 cents, click here.

 

I also have a link to a video that shows this exact coin in action here.

 

I'm selling this one mainly to see how much interest there is in something like this. Even though I'm using a lathe, it's still a slow process. This coin took about 3-4 hours to make. You have to go slow and careful or you damage it. Is this something geocachers would be interested in?

 

Dave

 

SDGeoCoin1.jpg

 

SDGeoCoin2.jpg

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I've thought of using small magnets. They make very very small rare earth magnets that are quite strong. One way would be to hold it on securely with magnets and still be able to pop the 'lid' up. Another idea is to not bevel the lid so it won't pop up. You would have to use a stronger magnet against the front of the coin to "push" the back off with magnetism.

Dave

 

Maybe just glue small magnets into each side so they snap together? Pretty cool though! This is what we planned with the GCC Spy Coin, but we didn't realize that when they polished them at the end that it would mess up the tolerances. :P You're either pretty brave or pretty crazy to try it though! :P:P

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Yes, one coin has the back removed, so that removes the tracking number. I've been thinking about that, but I'm not sure that I can really do much with the unused number. Any suggestions?

 

Of course, I could also make a coin with two backs, and two tracking numbers... :o

 

Dave

 

SO, is the bottom coin ruined or would "they" have 2 tracking # - since you use 2 coins ;) ?

 

Now on the mean side of the coin, If the second one is ruined, I could see where "misplaced" coins could go :D

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