Gland design dovetail grooves metric
Dovetail grooves are used to hold the O-ring in place during installation or maintenance. This groove design is relatively uncommon as it is expensive to machine and should not be used unless absolutely required. The dovetail groove construction is only recommended for O-rings with bigger cross sections, .139 inch (3,53 mm) and bigger.
Surface Finish X groove top and bottom : for liquids X = 32 micro inches (0.8 μm Ra)
for vacuum and gases X = 16 micro inches (0.4 μm Ra) 8,4 7,25 6,25 6,80 1,5 0,5
groove sides: X = 63 micro inches (1.6 μm Ra) 9,0 7,80 6,70 7,25 1,5 0,5
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