Would you drive Car without learning to drive and expect not to crash.?? . . . . . Your wasting your time buying cutters until you learn more about the tool your using.
The question "what's the difference between Carbide and 2 flute cutters" says that you are not ready to cut anything. Certainly not soft metals like Copper ,brass.

The reason your breaking cutters isn't quality it will be mixture of user error and possibly machine strength. Probably 99% user error.!
Machine strength plays big part in cutting and becomes even more important when tool size gets small. Only with trial and error will you find what works for your machine. Unfortunatly this may mean breaking tools to learn.

So I suggest you go away and do some research about the difference in cutting tools so can select the correct type of tool for the job. Then invest speeds/feeds calculator which will give you base reference point to work from with different materials.
Take this base point and make decision based on your machines strength/weakness to how much need to reduce or can increase the cutting parameters.

But you at least need to learn the basic differences between cutting tools before getting into the CAR.!! . . . . . Else you'll always Crash.!