Ant Barrier for bee hives

This is an ant barrier device to keep ants out of a bee hive. 4 are required. Each is designed to mount on a four inch 3/8-16 threaded rod. The lower part of the ant barrier will hold mineral oil. All gaps are 1/2". In order to enter the hive, the ant climbs the threaded rod, climbs the oil cup then is confronted with a 1/2" wide pool of oil. The ants cannot cross the oil so cannot enter the hive. These have been 100% effective at keeping ants out of my hive. The cover is designed to dis