This piston ring compressor is an adjustable hand tool designed to compress piston rings for safe, even installation of pistons into cylinder bores. The 70–150 mm range covers small to medium bores commonly found in motorcycles, lawn and garden equipment, small petrol engines and many single‑ and twin‑cylinder applications, allowing rings to be held concentrically as the piston is pushed into the cylinder without distortion or damage.

The tool comprises a hardened carbon spring‑steel band with a corrosion‑resistant zinc‑plate finish and a forged steel tightening screw with a simple cam/ratchet style locking mechanism operated by hand. The band thickness and heat treatment provide the elastic tension required to compress most standard ring profiles. Measurement range is given in millimetres to ISO metric conventions (70–150 mm). No threaded drive or conventional headed fastener is required to operate the compressor; instead the hand‑operated cam screw tightens the band and a locking pawl holds it while the piston is fitted.

Typical applications include engine reassembly in automotive and motorcycle workshops, small engine servicing (ride‑on mowers, chainsaws, outboards), agricultural machinery maintenance and light engineering. The tool is suitable for cast‑iron and steel piston rings and for use with both single and multiple ring assemblies where uniform compression and axial alignment are essential to prevent ring breakage or seating damage.

Key benefits are the spring‑steel band’s retained tension for consistent compression, the zinc plating which reduces surface corrosion in workshop environments, and the simple cam‑lock action that provides rapid, repeatable operation without specialist equipment. The design is compatible with standard ISO/DIN metric piston diameters and fits the common ring profiles used across industry, making it a practical choice for general workshop and field service use.

Duchy Fasteners stocks this piston ring compressor in the 70–150 mm size and supplies it as single items and in small trade packs; please contact us for alternative sizes, larger quantity packs or to check current availability.