Convert from button measure to arms-length

Unit Definition (button measure)
The button measure is a unit of distance equal to 1/40 inch (0.635 millimeter), used to measure the thickness of buttons.

Unit Definition (arms-length)
An Arms length is standardized as a unit of distance equal to approximately 70 centimeters, or 28 inches. An arms length is the same as the modern Italian Braccio and very similar to the Turkish Pik.