Reshape a Coin to oval without grinding?

W

Will Leavitt

Joined
Jul 28, 2006
Messages
3,953
Working a project where I need to reshape a coin from round to oval without grinding. I need it stay flat, I can flat sand one side though...... Using a rubber molding compound and stretching it has been suggested. Any suggestions?
 
Yes, use one of the penny flatteners you see at most tourist stops. :)

I have LOTS of oval pennies.
 
Pennies place on RR rails and run over tend to be ovals. Hard to duplicate that amount of force, and they were copper when last I did it. You would need lots of leverage. Probably would help to heat it until softer.
 
Salors used to make rings by tapping 90% silver us coins with a spoon on a table. It does turn the coin concave. You could tap the raised edges flat in the same way.
 
A jeweler's rolling mill can make a coin oval in 1 or 2 passes. The coin will still be extremely readable. Look in the yellow pages for a jeweler who does custom jewelry.

If you can't find anyone local, pm me. ...Teddy
 
Goldsmithy said:
A jeweler's rolling mill can make a coin oval in 1 or 2 passes. The coin will still be extremely readable. Look in the yellow pages for a jeweler who does custom jewelry.
Click to expand...

That sounds fascinating. It hasn't come up in my work yet, but now I'm kinda itching to do it. Thanks for bringing it up, Will and thanks for the tip, Goldsmithy :)
 
I would suggest eating it with your dinner and just see what shape it is as it comes out. Wear rubber gloves.
 
Honestly Will, take an older coin, pre 1982?, and set up at your anvil and cold forge it with a polished hammer face and the smoothest part of your anvil face.

A jewerely mill would be best, especially if it's a special, specific coin.

There are a couple WIP's Tai Goo showed how to make his ferrules using a mill to shape and twist wire. I have one on my to buy list.

If you don't anneal the coin, and even if you do, hammering mostly raises the rim of the coin which might or might not be acceptable to your purposes.
 
The simple answer is in your allowance for one side to not matter. As said, a rolling mill will make short work of this, but you can do the same on the anvil with simple tools.

Take a silver 1$ coin and anneal it by heating to dull red, air cooling to black, and quenching. Next, mark a line on the back side with a marker on the axis you want to stretch. Now, set the coin with the face you want to keep down on the anvil. Place a 1" to 1.5" piece of smooth round stock on the center of the coin, and strike with a 3# hammer. Move the round stock a bit and repeat, going from one side of center to the other, repeating till you get to the end. Use the line drawn to keep the stretch going the direction desired. Repeat as needed. Anneal again each full pass, and when done, anneal one last time. The face side will be nearly unchanged beyond the stretching of details. The back can be left as is, or filed smooth.

Note, if your anvil is chewed up, put a smooth plate of steel on it to be the face against the coin.
 
You must log in or register to reply here.
Back
Top