Compass for Geometry 20in Precision Woodworking Compass - Large

Our review of the Compass for Geometry 20in finds it best suited to woodworkers, draughting hobbyists and anyone needing large, accurate circles. The single biggest reason to buy is the combination of a long 20in span and a lockable wing design that holds a set radius securely, making it practical for carpentry scribing and large-format drawing. Built from metal and described as rust-proof and scratch-proof, this compass aims to bring a sturdy, stable option when plastic or small compasses fall short.

Key Features

• Durable metal construction: High quality steely materials resist rust and scratches so the tool keeps working in a workshop environment.
• Large 20in capacity: The long span allows cutting or marking circles up to about 30 in diameter when using the adjustable wing.
• Lockable wing design: The wing clamp secures an adjusted radius so circles remain consistent while scribing or drawing.
• Fine tip and adjustment knob: A finely ground point and adjustment knob reduce slipping and let you control the pencil grip length precisely.
• Detachable, portable size: The stand detaches without tools for easier transport and storage while still offering large-circle capability.
• Multi-purpose use: Suitable for woodworking, drafting, metal work and leather work where larger radii and durable marking are required.

Who It's For

The compass is ideal for woodworkers, carpenters and technical illustrators who need to scribe or draw large circles with a dependable metal tool; its 20in span and lockable wing are particularly useful for laying out work on sheet goods or full-size patterns. The sturdy tip and rust-resistant finish also make it a good fit for busy workbenches where tools get regular use.

It is less suited for fine-scale school geometry or very small radius tasks where a compact or micro-adjustable compass would be better; several customers noted the size can be awkward for tight, delicate circles. If you primarily need small radii under a few inches, consider a smaller precision compass instead.

Pros & Cons

Pros

• Solid metal build that resists rust and scratches, giving long-term durability.
• Large maximum circle capability and a lockable wing for repeatable radii.
• Fine-point tip and adjustment knob provide accurate measurement and reduced slipping.
• Detachable design makes the stand portable and easy to install without tools.

Cons

• Size can be unwieldy for very small radius work or detailed classroom geometry tasks.
• Some customers reported mixed impressions on tip longevity, so heavy users should monitor wear.

Specifications

Product type	Large woodworking and drafting compass
Span	20 in (compass length); adjustable up to 30 in diameter
Materials	High quality steely metal, rust-proof and scratch-proof
Tip	Finely ground point for accurate marking
Adjustment	Knob switch and lockable wing for secure radius setting
Portability	Detachable stand, no tools required for assembly
Primary uses	Woodworking, drafting, metal work, leather work, scribing

Our Verdict

The 20in Compass for Geometry is a solid value for anyone who needs large, accurate circles in woodworking or drafting; its metal construction and lockable wing deliver repeatable results on projects where size and stability matter. Those who mainly do small-scale school geometry should look for a smaller tool, but for shop layout, pattern work and large-format drawing this compass offers dependable performance at a reasonable price.

Frequently Asked Questions

Can this compass mark very large circles?
Yes, the lockable wing and long span allow circles up to about 30 in in diameter when set fully.

Is the compass resistant to rust?
Yes, it is made from steely metal described as rust-proof and scratch-proof to suit workshop use.

Will it work for small radius geometry?
It can, but the size makes it less ideal for tight radii; a smaller precision compass is better for small-scale work.