



 
Hi David, I am assuming that this is one straight piece of railing as in the diagram.
d is the distance between the centre points of the first and last spindle and s is the distance between the centre points of adjacent spindles. Hence
There re 17 spindles so there are 16 spaces between adjacent the spindles and thus
Your tape measure probably is in sixteenths of an inch so
and hence the spacing between the centre points of adjacent spindles is approximately 8 7/8 inches. Check:
Thus in the total length this spacing will leave you almost half an inch short and thus you will need to adjust the last few spindles slightly so that the spacing looks uniform. Harley  


Math Central is supported by the University of Regina and The Pacific Institute for the Mathematical Sciences. 