"Padding" quantity required

Here's an example of what I'm trying to accommodate.  I need to saw bat
stock material to make a part that is 14 inches long.  In order to do
this, I need 15 inches of raw material in order to give me 1 inch of
material to hold (clamp) the material into the saw.  The product
structure calls for 14 inches of raw material because the finished part
is 14 inches long.

 

How do you "tell" MAPICS to order and issue 15 inches of raw material,
not 14 inches when I need to make one of these parts?  And, if the
process is such that multiple parts can be cut from a single piece of
raw material, how do you accommodate that?  For example,  I need three
of these 14 inch parts and I can saw them at the same time from the same
piece of bar stock.  So now, I would need 43 inches of bar stock (1 inch
+ (3 x 14)).