Stanley No. 20 Circular Plane – The Adjustable Plane for Curved Work

Introduction

The Stanley No. 20 Circular Plane is a specialized woodworking plane designed for shaping curved and circular surfaces. Unlike standard bench planes with fixed soles, the No. 20 features a flexible, adjustable sole that can be set to cut both concave and convex shapes. This made it an indispensable tool for furniture makers, pattern makers, and craftsmen working with arches, rounds, and curved moldings.

Today, the No. 20 is one of Stanley’s most distinctive and collectible specialty planes.

History

The Stanley No. 20 was introduced in the late 19th century and produced well into the early 20th century, during a period when specialized hand planes were essential to fine woodworking. It evolved from earlier flexible-sole plane concepts and became the standard circular plane offered by Stanley.

Its design filled a niche that could not be handled effectively by spokeshaves or fixed-radius planes, especially when working long, smooth curves.

Key Features

Adjustable flexible sole for convex and concave work
Thumbscrew adjustment mechanism to control sole curvature
Cast iron body with nickel-plated hardware
Standard Stanley plane iron with cap iron
Comfortable rear tote and front knob for controlled cuts

The ability to fine-tune the sole radius allows the No. 20 to plane a wide range of curves with surprising accuracy.

Specifications

Feature	Details
Length	Approx. 10″
Iron Width	1¾”
Sole Type	Adjustable / flexible
Adjustment	Thumbscrew-controlled curvature
Use	Convex and concave curved surfaces

Collector Value

Because the No. 20 was a specialty tool produced in smaller quantities than bench planes, it is highly sought after by collectors.

Excellent condition: $200–$350+
Good, complete user grade: $125–$200
Missing parts or repairs: Significantly lower

Value depends heavily on completeness, especially the sole mechanism, screws, and original hardware.

Restoration Tips

Ensure the flexible sole moves freely and evenly
Clean and lubricate adjustment screws lightly
Flatten and sharpen the iron carefully
Preserve japanning and avoid aggressive polishing
Confirm that the sole flexes symmetrically without binding

A properly restored No. 20 is fully functional and capable of excellent curved-surface results.

Conclusion

The Stanley No. 20 Circular Plane is a remarkable example of Stanley’s commitment to specialized woodworking solutions. With its adjustable sole and precise control, it remains one of the most effective hand planes ever made for curved work.

Whether you’re a collector building a comprehensive Stanley reference or a craftsman working on curved furniture components, the No. 20 Circular Plane stands as a unique and highly respected tool in Stanley’s legacy.

See More about the Stanley No. 20 Circular Planes