Determining rope spacing

Rillenabstand
The most precise measurement of rope spacing is obtained by measuring over all the ropes.
Rope spacing is:  distance from first to last rope
No. of rope spaces 


Example:   
No. of grooves: 
No. of rope spaces is:  number of grooves - 1 = 5 
Distance from first to last rope is:  100 
Rope space is::  distance from first to last rope
No. of rope spaces
Equals:  100 mm
      5 
Result:  20 mm