I designed a variable 2.5 rev. helix sweep (extruded on the cap and bottle).
.3 inch pitch on 1st revolution starting from the bottom going up
.09 inch pitch on the remaining rev's.
I used a continuous sweep with no breaks in the threads.
But every bottle & cap I looked at has breaks at certain degrees of each revolution.
Is there a formula or basic guide line to these breaks in each thread?