Engineering:Compass saw
A compass saw is a type of saw used for making curved cuts known as compasses, particularly in confined spaces where a larger saw would not fit.[1][2]
Characteristics
Compass saws have a narrow, tapered blade usually ending in a sharp point, typically with a tooth pitch of 2.5 to 3 mm (eight to ten teeth per inch),[2] but down to 1.3 mm (up to 20 teeth per inch) for harder materials and as long as 5 mm (as few as five teeth per inch) for softer materials.[1] They have a curved, light "pistol grip" handle, designed for work in confined spaces and overhead.[2]
The blade of a compass saw may be fixed or retractable, and blades are typically interchangeable. Partially retracting the blade can prevent flexing and breaking when cutting harder materials.[1]
Compass saws are suitable for cutting softer woods, plastic, drywall, and non-ferrous metals.[1][2] The pointed tip of the blade can be used to penetrate softer materials without the need for a pilot hole.[1]
Comparison with other types of saws
Compared with other saws designed for cutting curves, such as coping or fretsaws, compass saws have a larger blade and longer pitch (fewer teeth per inch). This allows them to cut faster, and to cut through thicker materials, but leaves a rougher finish.[2]
Compared with drywall saws, compass saws typically have a longer blade – at 15 to 30 centimetres (5.9 to 12 in) – and shorter pitch (more teeth per inch).[1][2]
Keyhole saws, also called padsaws or jab saws, feature shorter, finer blades and (often) straight handles, and are suitable for cutting extremely tight curves.[2][3]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 "What is a Compass Saw?". http://www.wisegeek.com/what-is-a-compass-saw.htm.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 "What is a compass saw?". http://www.wonkeedonkeetools.co.uk/handsaws/what-is-a-compass-saw/.
- ↑ "Keyhole saw". http://www.daviddarling.info/encyclopedia/K/AE_keyhole_saw.html.
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