Y Type Compression Spring Wire Dia.=0.4mm OD=3mm~5mm A2 Stainless Steel Spring

Measure the bore or housing inner diameter your spring will sit in — the spring OD should be 0.1–0.5 mm smaller than the bore for a guided fit. For free length, measure the uncompressed gap in your assembly and add your required travel distance. Select the matching OD (3 mm, 4 mm, or 5 mm) and the closest free length from the variant options above.

Spring rate depends on wire diameter, OD, free length, and number of active coils — all of which vary by variant. Because this product covers a wide range of lengths and diameters, the spring rate differs per variant. If you need a specific spring rate value for engineering calculations, please contact us with your selected variant details and we will provide the specification.

Yes. A2 (304) stainless steel provides solid corrosion resistance against moisture, humidity, and mild chemical exposure. These springs are well-suited for outdoor DIY enclosures, garden automation systems, and marine-adjacent applications where mild corrosion resistance is needed. For highly aggressive chemical environments (e.g., chlorinated water or strong acids), A4 (316) stainless steel would be more appropriate.

Y-type refers to the end coil geometry of the spring. These springs feature ends that allow stable axial seating on flat surfaces, reducing the tendency for the spring to tilt or buckle under load when used in guided assemblies. This makes them suitable for use in spring seats, plungers, and return mechanisms where consistent axial force is required.

Absolutely. These are a popular choice for 3D printer extruder preload assemblies, CNC fixture clamps, robotic gripper return mechanisms, and small linear actuator return springs. The 0.4 mm wire diameter and 3–5 mm OD range fits many standard M3–M5 guided spring pockets commonly found in maker and automation hardware.

For prototyping or single-unit builds, the 1 or 2-piece packs are ideal. For small production runs or workshop stock, the 10 or 20-piece packs offer better value per unit. The 50-piece packs are suited for bulk assembly work or when you need spares on hand. All pack sizes ship the same spring — only the quantity differs.

The 305 mm (approximately 12 inches) variant is a longer-travel option designed for applications requiring extended compression stroke, such as large return mechanisms or custom jig assemblies. Compression springs can be cut shorter using a rotary tool or spring cutter, though cutting may alter the end geometry and spring rate. For precision applications, we recommend selecting the closest standard length rather than cutting.