Here's a pair of brand new carbon motor brushes for the great old Sunbeam Mixmaster mixers, up through the model 12 (1967) and also many (but not all) of the later 70's models. For 3/16" square brush holders, these were used in models: K, 1, 3, 5, 7, 9, 10, 11, and 12, and I believe in most of the other very first models, too, but I'm missing one or two of the very earliest mixer motors here to verify that. 

These are very easy to replace in older (pre-'68) Mixmasters with the external Bakelite caps on each side of their motor. Just keep in mind that the motor's armature rotates horizontally, so these should be installed with their curve matching the commutator's curved horizontal surface (the brush's curve should be aligned the same way as the curved side of the mixer when sliding it into the brush holder). You can almost always re-use the original springs with these. I have a few used springs left here if needed, but not many.

If you have any questions or need any other Mixmaster parts, please feel free to ask me. I still have some 100 vintage Mixmaster motors on hand here for parts. I probably have what you need, at least in motor parts. 

If you should have any questions or need any other Mixmaster parts, please feel free to ask me. I stock some 150 vintage Mixmaster motors as a parts source (I also buy them if you have one to sell!)

I also have Sunbeam Mixmaster and toaster service manuals available. They're direct, high quality scans of the original factory service manuals my Dad and I have used for decades! Just ask.