[Micro Milling]

I have this hub motor and need to reduce the circle by 5-10mm.

I was wondering if I clamp the motor down to my milling table by the axle, I can spin this metal hub motor.

If I spin this motor under a end mill, can I reduce the metal around the motor and it will keep the round shape?

Here is a picture of someone who shaved down the outside of the motor. I marked in red exactly where I need to reduce the metal.

I don't have a lathe so I am hoping to do this with my milling machine. I have a harbor freight mini mill and I will probably have to raise the height of the z axis.

Thank you for any advice you can give me.

Attachment 301672

Here is a picture of someone who used a lathe to cut down the height of the motor. You can see the grooves left my the lathe.

Attachment 301674

Here is a motor before it was cut down, you can see the original black paint. Just to give you an idea of what it looks like before cutting it down.

[kawazuki]

Two ways that I immediately see.....1. Mount a lathe chuck on your spindle, mount and clock up the motor then use a lathe tool in a vise horizontally to turn the piece or
2. Use a rotary table to hold the motor - clamped or in a chuck and use that to turn under std mill / spindle end mill?
The picture of the one that was lathe'd isn't very pretty - dull tooling or poor set-up there!
Just out of interest - what is the effect on heat dissipation of you machining down the motor casing? Maybe not such a good idea?

[Micro Milling]

Two ways that I immediately see.....1. Mount a lathe chuck on your spindle, mount and clock up the motor then use a lathe tool in a vise horizontally to turn the piece or
2. Use a rotary table to hold the motor - clamped or in a chuck and use that to turn under std mill / spindle end mill?
The picture of the one that was lathe'd isn't very pretty - dull tooling or poor set-up there!
Just out of interest - what is the effect on heat dissipation of you machining down the motor casing? Maybe not such a good idea?

Thanks,

Which method do you think will work better? I didn't think of using the milling machine to spin the whole motor. I can remove the internals of the motor and axle and it would weigh around 8 lbs maybe.

I am doing this to lighten the motor as this motor is built into a rim. The heat dissipation isn't an issue because that steel ring only holds the magnets and doesn't get hot. Most of the heat is in the stator which sits in the middle of the motor.

[LongRat]

The outer ring carries magnetic flux so I'm sure the performance of the motor would be reduced if you remove this material. I don't think they would leave heavy material there if it wasn't necessary.
Having said that, if you want to do it, I think the rotary table solution is the way forward that Kawazuki suggested. If you can clamp the largest possible diameter in the rotary table you will get the best result. The turned example you showed probably has a poor finish mainly because the set up is insufficiently rigid, holding either on a small diameter or worse still on the shaft itself. Then you are putting cutting forces through the bearings of the motor which are not designed to take it.

[Fastest1]

Put it in the swingarm, spin the hub motor by hand and use a belt sander. The belt sander if held at an angle to the direction of rotation would keep the hub spinning slightly while grinding the areas you want to remove.