Rules of Thumb

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1. A stretch greater than 5% on the O-ring I.D. is not recommended because it can lead to a loss of seal compression.

2. A Groove depth is the machined depth into one surface, whereas a Gland depth consist of the groove depth plus diametrical clearance and is used to calculate seal compression.

3. To create seal compression the groove depth must be less than the seal cross section. To compensate for this compression, the groove width must be greater than the seal cross section.

4. Static applications are more tolerant of material and design limitations than dynamic applications.

5. The maximum volume of the O-ring should never surpass the minimum volume of the gland.

6. For reciprocating seals passing O-rings over ports is not recommended. Nibbling and premature wear and seal failure will result.

Apple Rubber Products, Inc. • 310 Erie Street • Lancaster, NY 14086 • 1.800.828.7745

1. Introduction

2. Products & Services

3. O-Ring Basics

4. Seal Types & Gland Design

5. Critical Operating Environmental Factors

6. Material Selection Guide

7. Special Elastomer Applications

8. Troubleshooting

9. Sizes & How to Order

10. Glossary of Terms

11. Rules of Thumb

12. Formulas

13. Seal Glossary

14. Bibliography / Trademarks