Convert from attometer to shaftment

Unit Definition (attometer)
An Attometer (or attometre) is equal to one quintillionth of a meter, or sometimes denoted as 10e-18 meters. The origin of the prefix is atten, the word for 18 in Danish and Norwegian.

Unit Definition (shaftment)
A shaftment, when used as a unit of length, is usually six inches or two palms, i.e. 15.24 cm (for the international inch). It is thought to be the distance from the tip of the outstretched thumb to the other side of the palm.In English this unit has mostly fallen out of use, as do others based on the human arm: digit (1/8 shaftment), finger (7/48 shaftment), palm (½ shaftment) hand (2/3 shaftment), span (1½ shaftments), cubit (3 shaftments) and ell (7½ shaftments).