Page 16: of Marine Technology Magazine (May/Jun 2026)

LANDER LAB #19 force is required, making assembly easier.

Picking a small gap requires more precise machining.

For a typical .070” cross-section o-ring, a diametral clear- ance of 0.002”-0.005” is allowed. That means a maximum radial gap on one side of 0.0025”.

Back-up ring: I recommend always using a back-up ring with a radial o-ring. They are cheap, take up little space, and are de- signed to keep an o-ring from extruding. (See note 4 above.)

Place the back-up ring on the low-pressure side of the o-ring.

The o-ring sees the pressure