Convert from bee space to mil

Unit Definition (bee space)
The Bee Space is an informal unit of distance used in beekeeping. In a hive, bees seal up an opening smaller than a bee space, and they fill a larger opening with new honeycomb. If an opening is equal to a bee space, the bees leave it open as a passageway. A hive can be disassembled to remove the honey if the individual comb frames are carefully spaced one bee space apart. This discovery, made by the British beekeeper Lorenzo Longstroth in 1852, is crucial to modern beekeeping. The exact size of the bee space varies somewhat with the strain of bees being raised, but it is generally very close to 1/4 inch or 6.5 millimeters.

Unit Definition (mil)
The mil is a unit of distance equal to 0.001 inch: a "milli-inch," in other words. Mils are used, primarily in the U.S., to express small distances and tolerances in engineering work. One mil is exactly 25.4 microns, just as one inch is exactly 25.4 millimeters. This unit is also called the thou. With the increasing use of metric units in the U.S., many machinists now avoid the use of "mil" because that term is also a handy slang for the millimeter.