Hi Junior Burger,
You are right to focus on getting a vintage machine if you want a real milkshake. In my opinion, the only choice is the Hamilton Beach model 40DM 3-spindle mixer (preferably in the classic Jadite green color). I have recently started collecting them (I have 3 machines: 2 green and one ivory). Once you've seen and used this particular machine, you will be interested in no others (although the Sterling Multimixer is second in line, even that doesn't compare to the 40DM, as it has only one motor, and a mechanical system to link it to the multiple mixing spindles). If you don't have the space or $$ to get a 40DM (expect to pay $350-$600 for a good machine), you may want to consider an older Hamilton Beach single-head mixer, such as a model 30 or model 33, but these definitely do NOT have nearly the class or nostalgia of a 40DM, and they only have 2 speeds (not 3, like a 40DM), so they won't give you the indescribable, superior milkshake that the 40 DM delivers.
The 40DM is the classic, quintisciential machine. Each of the 3 spindles have their own motor and switch controls. If one spindle is broken (or even if you remove a spindle/motor for repair), the other 2 can still be safely used in the meantime. Inside, each motor is mounted with 4 spring-loaded, cushioned mounting screws (like a car engine), making vibration and noise minimal. The base of the unit is made of porcelain-coated cast iron... its heavy and its really gorgeous when you see it in person. The head housing is painted in the same color as the base. The 40DM weighs about 45 lbs.
I have been learning how to remove the motors from these machines, in order to get them serviced. For you, I would advise getting a 40DM that is in 100% perfect working order... unless you are really handy with motors and want to take on the task of refurbishing, as a hobby. Don't beleive any sellers that say a mixer is perfect except "it needs a switch" or anything like that (unless the machine is severly discounted to reflect the fact that it needs work). Having said all that, the 40DM is built like a tank, and inside the top housing unit, there are of course the 3 motors. I have an e-mail picture of the inside of the motor head, so if you want to e-mail me about it, I'll forward it to you.
post edited by milkshake - 2010/08/13 14:25:29