Coin Pinger
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Silver coin guide
Roosevelt Dime (1946–1964) — ping test & specs
Silver Roosevelt dimes (1946–1964) are the last 90% silver dimes; the 1965+ clad coin weighs 2.268 g and rings differently. Same 2.5 g / 17.91 mm planchet as the Mercury and Barber dimes.
Opens the free tester with this coin preselected — audio never leaves your device.
Official specifications
| Weight | 2.5 g |
| Diameter | 17.91 mm |
| Composition | .900 silver (90%) |
Source: United States Mint. Coin Pinger checks measured weight and diameter against these values.
Expected resonance range
High confidence*| Mode | Expected ring | Recommended variance |
|---|---|---|
| c0d2 | 7.39–9.23 kHz | ±11.1% |
| c0d3 | 17.14–21.24 kHz | ±10.7% |
A genuine Roosevelt Dime (1946–1964) rings within these ranges at its c0d2/c0d3 vibration modes, fixed by its size and metal. The recommended variance is how far a genuine specimen's ring can sit from each center — built up in quadrature from real manufacturing tolerance and temperature (under 1%), phone-mic capture reproducibility (≈4%), an extra allowance on the fundamental for minting-asymmetry splitting, and a per-metal model-uncertainty term (largest for .9999 gold, whose modulus is least certain). This coin's band is widened further because circulated 90%-silver classics lose mass and edge crispness with wear, spreading their ring. The higher modes also carry a small thick-plate centre correction, since a real coin is not infinitely thin. The high-confidence tag reflects how well-established this metal's constants are: Computed from well-established silver elastic constants and cross-checked against same-size sibling coins. These are guidance bands, not exact values — see the methodology for the exact formula, or calibrate your own coin in the app for a specimen-exact reference and tighten each peak per coin.
Small-coin note: at 17.91 mm this coin is below the ≥25 mm sweet spot — its ring is higher-pitched, shorter, and quieter than a full-size coin's, and only two of its modes stay under the 20 kHz phone-mic ceiling. Tap close to the microphone in a quiet room, expect more retries, and lean harder on the weight and diameter checks.
* These are computed guidance ranges. Certain your Roosevelt Dime (1946–1964) is genuine but it won't match? Send us its ring — we'll dig in and improve the reference.
🎙 Submit sample pingsHow to ping test a Roosevelt Dime (1946–1964)
- Hold — grip the coin by its center (a nodal point) in a coin ping-test holder so the rim rings freely; a fingertip at the center is a last resort.
- Tap — strike the edge with a striker near the microphone.
- Read the verdict — MATCH or NO MATCH against the peaks above, plus weight and size checks.
Roosevelt Dime (1946–1964) — frequently asked
How much does a Roosevelt Dime (1946–1964) weigh?
The official specification is 2.5 g in .900 silver (90%) (source: United States Mint). Coin Pinger's weight check allows ±0.3 g by default. Circulated specimens lose a little mass to wear, so weigh toward the low side of that window.
What size is a Roosevelt Dime (1946–1964)?
17.91 mm in diameter, per United States Mint. Note the average disc thickness is less than the rim caliper reading — the raised rim and relief concentrate metal at the edge.
What frequency does a genuine Roosevelt Dime (1946–1964) ring at?
Its fundamental (c0d2) vibration mode is computed to ring in the 7.39–9.23 kHz range, with higher modes near 17.14–21.24 kHz. These are first-principles physics computations from the coin's published mass, diameter, and metal — not measurements of sample coins.
Why does my genuine Roosevelt Dime (1946–1964) ring slightly off the listed frequencies?
Wear is the biggest factor for the Roosevelt Dime (1946–1964): circulated 90%-silver classics lose mass and edge crispness, which spreads the ring across specimens. On top of that, phone-mic capture moves a genuine peak a few percent tap-to-tap (strike point, how you hold it, the mic itself). That's why this reference band is wider than a modern bullion coin's.
Does ping testing damage a Roosevelt Dime (1946–1964)?
No — the test needs only a light tap on the edge with a non-marring striker (a wooden pencil or plastic stylus works well), far gentler than normal handling. Hold the coin at its center so the rim can ring freely.