20 in Compass for Woodworking Precision Divider - Large Drafting Tool

Our review finds the 20 in Compass for Woodworking best suited to carpenters, woodworkers and technical drafters who need a heavy-duty, large-format divider. In this review the most convincing reason to buy is its combination of size and build: with 20 in legs that can scribe circles up to 43 in in diameter and an all-metal construction in No. 45 carbon steel, it handles large layout work consistently and locks securely for repeatable marks. It is a practical, no-frills tool for anyone laying out large arcs or transferring measurements on wood, metal or leather.

Key Features

• Large reach: 20 in legs allow drawing circles up to 43 in in diameter, making the tool suitable for large woodworking and layout tasks.
• All-metal construction: Made from No. 45 steel for higher strength and deformation resistance, which gives a solid, durable feel in hand.
• Lockable wing design: The locking wings let you set and secure a radius quickly for consistent repeat measurements and circle drawing.
• Pencil holder: Built-in pencil holder accepts standard pencils for easy replacement and resharpening while working on long runs.
• Versatile divider: Can act as a scribe or divider to transfer measurements between pieces or to duplicate lengths across a workpiece.
• Rust protection: Points are quenched and the tool is treated with anti-rust oil before packaging for better corrosion resistance out of the box.

Who It's For

The compass is aimed at professionals and serious hobbyists who need to lay out large arcs or transfer measurements on-site: carpenters, cabinetmakers, timber framers, metalworkers and leatherworkers will appreciate the long legs and heavy construction. Designers and teachers doing geometry or drafting demonstrations that require extra-large circles will also find it useful.

It is less suited to casual sketching, pocket carry or fine-scale drafting where a delicate instrument is required. If you need a compact, lightweight compass for small circles, a bench or studio-sized precision compass would be a better choice.

Pros & Cons

Pros

• Heavy, well-built all-metal construction gives confidence when scribing large radii.
• Long 20 in legs and a secure lock make repeatable, accurate circles up to 43 in possible.
• Pencil holder and scribe/divider capability add versatility across materials.
• Good corrosion protection and quenched points extend service life with normal care.

Cons

• Weight and size make it less convenient for small tasks or frequent transport.
• Some customers note the pencil holder can be tight for larger pencils and may require a specific pencil size.

Specifications

Product type	Large woodworking/divider compass
Leg length	20 in (each leg)
Maximum circle diameter	Up to 43 in (110 cm)
Material	No. 45 carbon steel (1045 / S45C / C45 equivalent)
Locking mechanism	Lockable wing design
Pencil	Pencil holder included (pencil not included)
Finish / protection	Quenched points and anti-rust oil treatment

Our Verdict

The 20 in woodworking compass is a practical, heavy-duty layout tool for anyone who regularly needs large radii and durable repeatable marking. Its long legs, solid No. 45 steel construction and lockable wings offer reliable accuracy and longevity, making it good value for tradespeople and serious hobbyists; those requiring portability or very small-scale drafting should consider a smaller alternative.

Frequently Asked Questions

How large a circle can this compass draw?
The legs extend to draw circles up to 43 in in diameter.

Does it include a pencil?
It includes a pencil holder but the pencil itself is not included.

Is the tool corrosion resistant?
Points are quenched and the tool is treated with anti-rust oil before packaging to reduce corrosion risk.