Measure the thickness of the material you are bolting through, then add enough thread engagement — generally at least 1.5× the bolt diameter (≈30mm for M20). For example, a 50mm thick beam typically requires a 70mm (≈2.76") or 80mm (≈3.15") bolt. Lengths from 100mm onward have a partial thread shank (b=80mm), which is better suited for thicker substrates where a smooth shank reduces stress concentration.

Working load limits vary by installation angle and substrate quality. M20 eye bolts in 304 stainless steel generally support a vertical working load of around 1,000–1,500 kg when properly installed in a rated anchor point. Always derate for angled loads — a 45° sling angle typically reduces capacity by around 30%. Consult a structural engineer for safety-critical or overhead lifting applications.

Yes. 304 stainless steel offers strong resistance to rust and oxidation, making these eye bolts well-suited for outdoor, coastal, and light marine environments. For highly aggressive saltwater immersion or chemical exposure, 316 stainless steel is generally recommended. If you're unsure, contact us to confirm suitability for your specific environment.

These eye bolts use the standard ISO metric M20 coarse thread (pitch 2.5mm), compatible with any M20-threaded nut, drop-in anchor, threaded insert, or rod coupler. They are not compatible with imperial UNC or UNF threads. If your existing hardware is imperial, you will need an adapter or a different bolt standard.

Lengths 70mm, 80mm, and 90mm are fully threaded (b = full thread) — the thread runs the entire shank length, ideal for thinner materials or when you need maximum thread engagement. Lengths 100mm through 200mm have a partial thread shank (b = 80mm), leaving a smooth unthreaded section. This smooth shank reduces stress concentration in thicker substrates and is the standard configuration for longer structural eye bolts.

Yes. The closed-loop eye head is designed to accept shackles, carabiners, wire rope clips, and catenary wire tensioners. Ensure the eye inner diameter is compatible with your connecting hardware — M20 eye bolts typically have an eye inner diameter of approximately 20–22mm, though we recommend confirming this for your specific application. Contact us if you need exact eye dimensions before ordering.

For through-bolt installations (bolting through a beam or plate), a matching M20 nut and washer are recommended to distribute the load and prevent pull-through. For threaded insert or drop-in anchor applications, the bolt threads directly into the anchor — no nut is required. Nuts and washers are not included and should be sourced separately.