Looks like a bit of fun.

The drawings could be made with Excel Shapes and updated when the cell values change.

Some questions:
1. How far from the left and right edges are the bolts - i.e how do you calculate p?
2. How far from the top and bottom edges are the bolts - is B equal to ((number of bolts / 2) * (bolt diameter)) + ((number of bolts + 1) * g)
3. What is x in the bottom diagram?
4. Is D in the bottom diagram the same as D in the top diagram?