Rules of Thumb

Rules of Thumb: #1-6

Welcome to the first post in our Rules of Thumb series. Reading these rules will supply you with a greater knowledge and understanding of sealing principles. Here are our first few tips to consider when it comes to installing and maintaining the life of your O-ring:

1. Stretch greater than 5% on the O-ring I.D. isn’t recommended because it can lead to a loss of seal compression.

2. Know the difference between Groove and Gland depth. Groove = machined depth into the one surface. Gland = groove depth plus diametrical clearance, used to calculate seal compression

3. If you want seal compression, groove depth must be LESS than the seal cross section.  To compensate for this compression, the groove width must be larger than the seal cross section.

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

5. Make sure the maximum volume of the O-ring never surpasses the minimum volume of the gland.

6. Passing O-rings over ports is not recommended for reciprocating seals – nibbling and premature wear and seal failure will occur!

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