Pulley grub screw location

[booski]

Unfortunately, I don't have access to a mill or broach set and we are talking of very small diameters here. I have found online (from china however) adjustable reamers.
I understand that a cheap reamer may not be wholly accurate whilst an adjustable one you can step it up until you get the right size. The trouble still arises when dealing with small bore like 1/8" for the motor.

Obviously, I could simply turn a length of aluminium down to a reasonable size, drill to 3.1mm and press onto motor shaft. Then with the motor shaft in the lathe, turn the aluminium down to the correct size.

There are many methods, I know, but I'm not really a machinist. I've completed basic machinist courses to the best in class and done various pieces of machining in my old job of which I was frequently called upon to perform but nothing really to this degree of accuracy.


Just to throw another spanner in the works, I have a reasonable size piece of aluminium available to me, what if I were to machine a V-pulley to be used with o-rings instead of buying T2.5 / T5 pulleys and machining them in the hope I don't ruin them?