When I first held a 1792 US half dime, its rough edges told stories of coinage evolution. The edge of a coin isn't just metal - it's anti-fraud technology perfected over centuries.
The edge of a coin is called the "third side1," with specific names like reeded, lettered, or plain edges depending on design and function. These features prevent counterfeiting and help identification.
Let's explore why edges matter more than you think - from historical scandals to modern manufacturing secrets.
What Is the Coin Clipping Scandal?
Shakespeare warned about coin clippers in Measure for Measure. From 1696, England faced economic chaos when criminals shaved precious metal from coin edges.
Coin clipping was the illegal practice of shaving metal from coin edges, reducing their value while keeping face validity. This forced mints to develop security edges.
How It Changed Money Forever
Isaac Newton's solution as Warden of the Mint:
| Year | Solution | Impact |
|---|---|---|
| 1696 | Reeded edges | Made clipping obvious |
| 1701 | Lettered edges | Added text verification |
| 1725 | Edge numbering | Enabled batch tracking |
The 1699 Great Recoinage replaced £6.8M clipped coins - equivalent to $1.5B today.
How Are Coin Edges Made?
Modern edge creation combines force and precision. Our factory uses 200-ton presses with specialized collars.
Coin edges are made through striking (hammering blank metal) or milling (cutting grooves), using collar dies that shape edges during minting. Advanced factories now use CNC-machined dies.
The 3-Step Edge Creation Process
- Blank preparation: Zinc alloy discs cut to ±0.01mm tolerance
- Edge forming:
- Reeded: 115° diamond-cut grooves
- Lettered: Rotating laser engraving
- Quality control: Edge thickness measured with laser micrometers
What Are Coin Sides Called?
Novice collectors often confuse "obverse" with "reverse". The terminology dates back to Roman denarius coins.
The front side is called the obverse (heads), showing primary design. The back is the reverse (tails). The edge is considered the third side. US law mandates "In God We Trust" on obverse.
Design Rules by Country
- USA: President faces left on obverse
- UK: Monarch alternates direction with each reign
- Japan: Chrysanthemum reserved for imperial coins
What Is a Lettered Edge on a Coin?
The 1907 Saint-Gaudens double eagle proved lettered edge2s could be art. Today, our laser engravers achieve 0.2mm character height.
A lettered edge has raised text or symbols around the coin's circumference, originally used for anti-counterfeiting messages like "DECUS ET TUTAMEN" (ornament and safeguard).
Modern Lettering Techniques
| Method | Precision | Speed | Cost |
|---|---|---|---|
| Laser | ±0.005mm | 15s/coin | $$$ |
| Engraved collar | ±0.01mm | Instant | $$ |
| Post-strike | ±0.1mm | 45s/coin | $ |
Why Custom Edges Matter Today
Last month, a client needed RFID-embedded edges for smart medals. This wasn't possible 5 years ago.
Modern edges can include:
- Micro-engraved QR codes
- Tamper-evident grooves
- Dual-tone electroplating
- Hidden UV markings
[Your Custom Coin Solution]
After 12 years crafting coins for 37 countries, we understand edge engineering. Our ISO 9001-certified factory combines historical techniques with AI quality control.
Why professionals choose us for custom edges:
✅ 18K gold plating that lasts 10+ years
✅ 0.01mm precision laser engraving
✅ MOQ from 100 pieces
✅ 15-day production with real-time tracking
[Contact Joshua at info@inimaker.com for free edge design consultation]
Conclusion
From clipped coins to laser-etched security edges, the third side remains money's silent guardian. Next time you flip a coin, check its edge - it's history in your hand.
