Aerospace Recommended Practice "ARP568" defines Uniform dash numbering for O-ring. In 1971 SAE replaced this name as AS568 (Aerospace Standard).
There are 2 classes of tolerances for Internal diameters. Most common c/s - 1.78, 2.62, 3.53, 5.33, 6.99 and some additional ARP 900.
Each 3 digit...
Quite an interesting thread. Were you able to decide on oil and breather?
Shaft seals I believe you may have to go for material that is compatible with oil as well as water.
I would probably look for PTFE based rotary seals.
Seal lip can be designed to withstand the pressure from internal...
Unfortunately there are no standards for conical sealing. O-ring being round in Shape, after assembly need to have same squeeze / fill in these type of grooves too.
Only concern here, as you rightly mentioned is size selection. In these cases I would prefer to go for O-ring ID size either equal...
