Stanley No. 20 Circular Plane – The Premium Compass Plane for Perfectly Shaped Concave & Convex Curves
1. Introduction
The Stanley No. 20 Circular Plane—also known as a compass plane—is one of Stanley’s finest specialty tools. It is designed specifically for shaping concave and convex curves in wood. Unlike the No. 113 (with a flexible steel sole), the No. 20 features a rigid cast-iron frame with a flexible steel sole plate, offering significantly improved stability, precision, and rigidity.
The plane in the picture above is nickel plated which was done up to 1919. After 1919 the casting was japanned with nickel trim pieces.
Patternmakers, boat builders, chairmakers, instrument makers, and fine furniture builders relied on the No. 20 to shape flowing curves with accuracy that cannot be achieved with flat planes, spokeshaves, or sanding alone. Its refined radius-adjustment mechanism and robust sole make it a favorite among both users and collectors.
This is a complete guide to the Stanley No. 20 Circular Plane—its history, features, usage, restoration, and value.
2. History of the Stanley No. 20 Plane
The No. 20 was Stanley’s premium-level compass plane, introduced to provide a more accurate and rigid alternative to the more common No. 113.
Historical Highlights
- In production from 1897 to 1958
- Body was nickel plated prior to 1919, after that it was japanned
- Designed as a more precise, higher-quality compass plane
- Featured a rigid system for adjusting curvature
- Often paired with the larger No. 13 or the flexible No. 113
- Manufactured well into the 20th century (1958)
- Sweetheart-era versions are especially desirable
- The Stanley No. 20 was acquired from Leonard Bailey’s sale of Victor Planes, tools, and patents in 1884
Because of its superior performance and durability, the No. 20 became the tool of choice for professional curve-forming work.
3. Manufacturer Background – Stanley Rule & Level / Stanley Works
Stanley, founded in 1843, is famous for producing the widest array of woodworking planes ever made. The No. 20 reflects Stanley’s dedication to:
- Professional-grade specialty tools
- Durable engineering and precision machining
- Specialty woodworking solutions
- Tools optimized for patternmaking and curved work
The No. 20 is recognized as one of the most accurate and stable circular planes Stanley ever manufactured.
4. Design and Features of the Stanley No. 20 Circular Plane
The No. 20 features a premium and more rigidly engineered mechanism than the No. 113, making it better suited for tight radii and professional use.
Specifications
- Length: approx. 10 inches
- Iron width: approx. 1⅝ inches
- Weight: approx. 3 lbs
- Blade orientation: bevel-down
- Curvature range: concave → flat → convex for radius greater than 20 inches
- Body: cast iron frame with flexible steel sole
Core Features
- Curvature-adjusting top wheel for bending the steel sole
- Robust curved sole support system for consistent shaping
- Bevel-down cutter with depth-adjustment wheel
- Rigid cast-iron frame (stronger than No. 113’s open style)
- Precision-machined sole and ribs
- Adjusts smoothly from concave to convex
- Comfortable front knob and rear handle
Why the No. 20 Stands Out
- More stable and rigid than the No. 113
- Produces smoother, more accurate curves
- Ideal for professional trades
- Less prone to chatter or flex distortion
- Considered the highest-performing circular plane Stanley produced
Patents for the Stanley No. 20 Circular Plane
- E.A Shades Design Patent – February 7, 1893
- Traut’s Disc Pivot Lateral – July 24, 1888
- E.V. Higbee’s Lever Cap – July 18, 1933
- A.W. Stanley Circular Plane Sole Adjustment – September 8, 1903, 738,500
The No. 20 is the “furniture maker’s” compass plane—more precise and refined than its counterparts.
5. Usage & Applications
The No. 20 is a dedicated tool for curved woodworking surfaces, excelling at shaping and smoothing complex radii.
Ideal Uses
- Furniture components with curves
- Chair arms, legs, and rockers
- Boat interiors and curved fitting panels
- Patternmaking & mold-making
- Musical instrument construction
- Sculptural and architectural woodworking
- Shaping concave or convex surfaces with precision
The No. 20 is capable of smoothing curves that sandpaper, rasps, or spokeshaves cannot efficiently refine.
6. Restoration of a Stanley No. 20 Circular Plane
Because of its metal curvature mechanism, the No. 20 requires careful restoration.
Typical Restoration Steps
- Disassemble the adjuster, sole plate, lever cap, and cutter
- Remove rust using Evapo-Rust or a mild acid bath
- Clean the sole curvature supports to restore smooth functionality
- Sharpen the iron (a standard Bailey-style bench plane iron)
- Lubricate the main curvature wheel and pivot points
- Preserve original japanning and nickel plating when possible
- Test curvature range to ensure smooth concave/convex transitions
Optional Upgrades
- Replacement blade (Hock, Veritas)
- Polished sole edges for smoother cutting
- Replacement adjuster hardware (if worn)
Restoration Mistakes to Avoid
- Over-bending the sole (can create permanent distortion)
- Overlapping near the front and rear sole pivot points
- Removing japanning or nickel plating unnecessarily
- Using power tools on delicate brass hardware
A restored No. 20 can shape curves as well as many modern premium tools.
Tools & Supplies for Old Plane Restoration
These are some of the most used tools for restoring old woodworking tools.
Rust Remover
Abrasive Pads
Brass Brushes
WD-40
Paste Wax
Steel wool
Equivalent Supplies on Amazon
7. Collectability & Value
Collectors consider the No. 20 more desirable than the No. 113 due to its relative scarcity and superior engineering.
Typical Value Range
- User-grade: $125–$200
- Good condition: $200–$325
- Sweetheart-era: $325–$500
- Excellent or boxed examples: $500–$700+
Factors That Influence Value
- Integrity of flexible sole mechanism
- Smooth operation of curvature wheel
- Japanning and hardware condition
- Sweetheart-logo irons
- Casting condition with no cracks
- Completeness (especially adjuster hardware)
The No. 20 is a strong investment for tool collectors.
Collectors consider the No. 20 more desirable than the No. 113 due to its relative scarcity and superior engineering.
Typical Value Range
- User-grade: $125–$200
- Good condition: $200–$325
- Sweetheart-era: $325–$500
- Excellent or boxed examples: $500–$700+
Factors That Influence Value
- Integrity of flexible sole mechanism
- Smooth operation of curvature wheel
- Japanning and hardware condition
- Sweetheart-logo irons
- Casting condition with no cracks
- Completeness (especially adjuster hardware)
The No. 20 is a strong investment for tool collectors.
8. Finding Manuals, Parts & Additional Resources
Documentation Sources
- Stanley type studies
- Blood & Gore compass-plane listings
- Early 1900s Stanley catalogs
- Stanley Collectors Club publications
Replacement Parts
- Stanley No. 20 Circular Plane Parts on Ebay
- Replacement irons (Hock Tools, Veritas)
- Adjustment wheels and hardware (eBay, collector forums)
- Reproduction screws and knobs available from tool restorers
Because the No. 20 is more robust than the 113, original parts are often in good condition and easier to restore.
9. Final Thoughts
The Stanley No. 20 Circular Plane is one of Stanley’s most brilliant achievements—a highly refined, durable, and precise tool for shaping curves. Its rigid cast-iron frame, adjustable flexible sole, and dependable depth-adjustment mechanism make it a cornerstone tool for professional curve-based woodworking.
For collectors, the No. 20 represents some of Stanley’s finest specialty-plane engineering. For woodworkers, a well-tuned No. 20 performs like a premium radius plane that is still unmatched today.
A restored No. 20 belongs in any serious woodworking shop or vintage tool collection.
Quick Reference Summary
| Category | Details |
|---|---|
| Model | Stanley No. 20 Circular Plane |
| Manufacturer | Stanley Rule & Level / Stanley Works |
| Era | 1890–Mid 20th Century |
| Length / Iron | ~10″ / ~1⅝″ |
| Key Feature | Rigid body + flexible steel sole |
| Best Uses | Concave/convex shaping, patternmaking |
| Rarity | Moderate–High |
| Typical Value | $125–$700+ |
| Restoration Difficulty | Moderate |
| Collectability | High—especially Sweetheart-era |
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Stanley No. 20 Circular Plane Photos
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