Study Major Error Categories and Diagnostics
4 hoursLearn to distinguish die cracks, cuds, off-center strikes, broadstrikes, and hub doubling from post-mint damage.
Intermediateongoing
Error Coin Hunting Guide
Complete guide for error coin hunting — step-by-step workflow, tools, checklist, and expert tips to get started.
variety huntersroll searchers
Workflow
Source Bank Rolls and Mint Bags Strategically
ongoingOrder boxed coins from banks, focus on known productive dates, and track search cost per find.
Search, Magnify, and Sort Finds
2 hours per rollExamine each coin under 10× loupe for rotation, doubling, and strike anomalies; set aside candidates for confirmation.
Confirm Varieties and Slab or Sell
1 hour per findVerify attributions against Wexler or CONECA listings, then submit valuable finds for attribution or sell raw to variety dealers.
Tools Used
- NotepadPrimary
Log roll sources, search dates, error type candidates, and confirmation references for each find.
- Inclusion Grading ScorePrimary
Apply structured diagnostic criteria to distinguish genuine hub doubling from machine doubling artifacts.
- Image CompressorSupporting
Capture macro photos of suspected errors for online attribution confirmation before slabbing.
- Percentage CalculatorReference
Track find rate and cost per error against roll search expenses to evaluate hunting profitability.
Checklist
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Research
Equipment
Sourcing
Skills
Organization
Verification
Reference Materials
Common US Roll Search TargetsTable
Productive series for beginner error hunters.
| Series | Error Type | Search Tip |
|---|---|---|
| 1955 doubled die cent | Hub doubling | Check LIBERTY and date |
| Off-center cents | Strike error | Any date — value scales with off-center % |
| Nickels 1938– | Die cracks, cuds | Jefferson collar errors rare but exist |
| State quarters | Die breaks | Check extra leaves and die chips |
Off-Center Value EstimateFormula
Premium increases with off-center percentage when date and mint mark remain fully visible on retained planchet.
PMD ExclusionStandard
Post-mint damage including vending machine reeding, counterstamps, and environmental corrosion carries no mint-error premium.
Machine Doubling Trap
Flat shelf-like doubling on cent letters is machine doubling — worth face value only.
Weight Check
Wrong planchet and clipped planchet errors show on scale before loupe confirms.
Bank Limits
Ordering excessive boxes without returning coins burns bank relationships — search ethically.
Safety Notes
- Handle coins by their edges during roll searching — hours of handling causes noticeable wear on high points.
- Eye strain from loupe work requires breaks — use adequate task lighting to reduce fatigue.