Technical tools
Six free tools for the questions that come up before you order a seal: what size the groove should be, whether the material survives the medium, what an AS568 dash number converts to, how to measure an old ring, and why the previous seal failed. They run in the browser, no sign-up.
Groove calculator
Calculate the correct groove dimensions for static and dynamic sealing per ISO 3601-2.
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Chemical compatibility
Compatibility chart of the most-used materials (NBR, EPDM, FKM, FFKM, silicone) against the 400 most common media.
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Size converter
Convert between the American AS568 standard and metric dimensions — full series 001 through 475.
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How to measure a ring
Five proven methods to accurately measure an existing O-ring — caliper, template, and reference comparison.
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Seal failure diagnosis
The wizard identifies the probable cause of an O-ring or shaft-seal failure from the observed symptom and recommends a replacement material.
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Radial shaft seals (gufera)
Technical reference for radial shaft seals — DIN 3760 types, materials, operating limits and common d×D×b dimensions.
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Which tool you need
Each tool answers a different question. Here is when to reach for which.
- What size should the groove be?
- Groove calculator. Enter the inner diameter and cross-section of the ring and the tool returns groove width, depth and corner radius from the recommended ISO 3601-2 ratios — separately for static and dynamic installation, with squeeze and stretch in percent.
- Will the material survive the medium?
- Chemical compatibility chart. Ten materials (NBR, HNBR, EPDM, FKM, VMQ, PTFE, FFKM, CR, AU, NR) against 400 industrial media in eight categories — acids, bases, solvents, oils, fuels, refrigerants, food media and other. With a filter by medium and CSV export.
- What does an AS568 number convert to?
- Size converter. It works both ways: from an AS568 dash number in series 001-475 to millimetres, and from a measured diameter and cross-section back to AS568. The five series have fixed cross-sections — 1.78, 2.62, 3.53, 5.33 and 6.99 mm.
- How do I measure an old ring accurately?
- Measuring guide. Five methods depending on what you have at hand — caliper, calibrated pin, optical comparator, ruler, or an imprint for a distorted ring. Always measure the ring outside the groove; inside the groove it is compressed and the cross-section reads low.
- Why did the previous seal fail?
- Failure diagnosis. Pick the seal type and the symptom you see on the old part — the guide covers 12 O-ring failure types and 13 shaft-seal failure modes, each with a probable cause, a fix and a recommended replacement material.
- Which shaft seal fits the shaft?
- Shaft-seal reference. DIN 3760 construction types and their industry codes, lip materials with temperature and surface-speed limits, shaft and housing requirements per ISO 6194-1, and a table of common d×D×b sizes. Reference only — no prices, no products.
How the tools fit together
Most seal orders start the same way — an old ring or a drawing in hand and a decision to make about what to order. The sequence that works is measure, convert, then choose the material. Measure the inner diameter and cross-section of the ring outside the groove first. If you have an American dash number instead of a dimension, convert it to millimetres. The size is fixed by the design and cannot be changed; the material can, which is why it comes last.
If you are not replacing an existing seal but designing a new gland, start at the groove instead. The groove calculator works from the recommended ISO 3601-2 ratios, where both groove width and groove depth are multiples of the ring cross-section. Depth sets the squeeze: static installations aim for roughly 20 to 25 %, dynamic ones for around 10 %, because in motion wear and friction dominate. A groove that is too shallow deforms the ring permanently; one that is too deep never builds enough squeeze and the joint leaks.
Material is chosen by medium, temperature and pressure — in that order. The chemical compatibility chart is a first filter, not a test report: published ratings apply to a clean medium within the stated temperature range, while real plant conditions usually combine several substances, pressure cycles and cleaning agents. Ratings are taken from seal manufacturer handbooks, and where sources disagree we publish the stricter one.
When a seal fails earlier than it should, fitting the same part again does not solve anything. The failure diagnosis walks from the symptom — a hardened and cracked ring, an extruded edge, a worn shaft-seal lip — to the probable cause and to a material that survives it. For shaft seals the reference page completes the picture: shaft roughness and hardness, runout and the lead-in chamfer affect service life as much as the material does.
The tools are public and reference-only — no registration, no order required. Once you have both the size and the material, the full tables live in the Dimensions section: 349 AS568 sizes, 360 ISO 3601 sizes and 234 JIS B 2401 sizes, each linking to the matching ring in the catalogue.