Tri-Roll Thread Gage 1/8"-NPTF OD Comparator
1/8" NPTF Tri-Roll Thread Comparator
Outiside Diameter
Features -
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Frame: C3
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Gauging Points: 1-8" - NPTF
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Stand: 101
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Indicator: Johnson Dial .0025" *Note: Lens is loose
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Gaging rolls are interchangeable
NPTF (National Pipe Taper Fuel) threads have the same taper of 3/4" per foot, and 60º thread angle as NPT. However, they do differ significantly in the crest and root truncation requirements. Tolerance limits are thigter for proper "dryseal" assembly.
As mentioned above, the lens cover is loose. Is included because it is an original Johnson dial indicator. Will repeat.
Well miantained.
Made in USA