The lachter (also Berglachter) was a common unit of length used in the mining industry in Europe, usually to measure depth, tunnel driving and the size of mining fields; it was also used for contract work.
A lachter was roughly equal to the amount which a man could contain within his outstretched arms.
The lachter was - with regional differences - subdivided into Achtel (also called a Spann, Gräpel or Gröbel), (Lachter)Zoll, Primen (or Prinen) and Sekunden: In the 19th century a decimal system of subdivision was established: Like other units of measure, the lachter varied in length depending on the region, but there could also be differences in length within the same region.
The specification and use of conversion tables only makes sense if it is known for certain, where and at which times the values were valid.
Some examples: A Lachterschnur was an oiled, 10–12 Lachter long cord, used as a measuring device.