Doug Fattic 

Just to be clear under normal circumstances a properly brazed eyelet holding a rack on a dropout is unlikely to break. However if a bicycle with a loaded rear rear rack falls over and if the rack or load takes the force of the fall, it is a possibility that the brazing gives way. There isn't enough brazing area between the dropout and eyelet to hold with a strong blow. This can be a marketing problem for a builder. All the customer has to say is "I had a braze-on put on by Doug and it broke". They may or may not give context that explains fully why it broke. Even the slightest hint of something breaking can discourage a potential customer.

The solution is a simple one. The braze-on boss holding the strut of a rear rack doesn't have to be on top of the dropout. It can be a water bottle boss brazed into the bottom of the seat stay just above the dropout. It simply will not break off there. Some of my frame building class students have chosen dropouts that they liked that did not have enough eyelets. Their solution was to braze on the boss holding either the fender or rack into the bottom of the fork blade or seat stay. That way it works just fine.

Here is an example of a bicycle frame made in my class and painted in my shop. The student chose Henry James stainless steel rear dropouts because he really liked the look of them and the faces could be masked so the skewer doesn't damage the paint. However stainless can't be brazed with brass it has to be done with less strong silver. In this case the student solved the problem by brazing a stainless steel water bottle boss on the bottom of the seat stays. This allows him to be able to load up his rear rack as much as he wants and not worry about it. I'm assuming he will also put his fender struts on the same boss.