Frequently Asked Questions

In the beginning, the bosses (profiles) were cylindrical and centered on the cavity. The boss created a consistant locating spot for the fixture that put in the bolt through holes. The first step in machining sandwiches was to put in the cavities and this was done using big old #4 Warner-Swazey turret lathes. Adding the circular boss was practically free at this point. When 2 or more sandwiches are stacked they look designed rather than a random stack of blocks. This was deemed esthetically pleasing and became a Sun trademark. You can spot Sun sandwiches from across a factory floor. We switched to CNC in the early 80's but kept the circular boss. At this time the first sandwich with 2 cavities on one side was designed, the YFCG XHN AA. Obviously we could not use a circular boss centered on a cavity; we tried a partial circular boss centered on both of the cavities, but the resulting appearance was poor. The solution was a rectangular boss with radiused corners. The resulting profile was pleasing and more modern looking than the circular boss and served a functional purpose--less material had to be removed. We changed all the other sandwich bosses to match. We have applied the boss profile to some custom manifolds.....just because it looks good.