Hehehe good guess , ME/EE degrees.
Also: for those reading, there are 2 standards USS and SAE. Either the washers you find are 5/64" (USS) or 1/16" (SAE) in thickness for a 3/8" washer. Most likely people using 3 washers are using SAE std. with them stacking to roughly the 1/6" gap hogmeat utilizes.