Doubt about 3/4 14 DRYSEAL NPSF THREAD 1

[maquina01]

I have a hole with 3/4 14 npsf thread and verify with L1 and L3 gage, when I veryfied with L1 gage is ok, and when it veryfied with L3, pass through all the hole, what you think is the problem, conicity, big diameter before threaded

 

[Tmoose]

threads refence off the pitch diameter, not the minor (inner) diameter