The BOI approved for investment promotion in the business of manufacture of type of product each project as follows;
BOI project #1 : Metal part for electronic product such as Shaft, Sleeve and Hinge etc.
BOI project #2 : Metal part for Spindle motor such as Sleeve (using only Hard disk drive)
BOI project #3 : Metal products, including metal parts such as Sleeve, Holder, Stopper, Nut, Coller and Bush (using for Electronic and automotive parts)
So, if it's making from Brass I think we can use privilege under BOI project 3.