same design for SK3s?
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Across the board… nobody does anything different.
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IMO the best solution is what Hobbyking does with their SK3 and SK8 6374 motors: Use a skirt bearing that supports the other end of the can.
Yeah yeah, I know, that’s a whole can of worms, takes up room for stator/windings, makes it more complicated and difficult to manufacture, yadda yadda.
But it works.
The other thing I can think of is to make the back plate of the can (or at least part of it) out of something stronger than aluminum. A steel piece shaped like this:
tightly press-fit onto the shaft with a key or other rotation-preventing mechanism, and then screwed to the can. That would greatly reduce the tendency for the bore to get wobbled out and loose over time.
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The whole design flaw is that of using a small diameter, hardened steel shaft in a shallow, soft aluminum bore. If the bore was deeper than ~1-1.5*the diameter of the shaft, there would be no problem.
If the bore were something with a significantly higher yield strength than 6061(E.G. steel), then there wouldn’t be a problem.
If the shaft were to have a big mushroom end to spread out the pressure, then there wouldn’t be a problem.
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Yeah, Ideally both of those are good ideas.
We did alter the inside to have a much longer support for the rotor on the motor shaft.
But do need to add another sort of keyway option as well.
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pics are all above in this thread
Yeah, I acknowledge that your motors are better designed, just not better enough 
There’s only so much space there for making the aluminum more beefy.
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That’s good, but I’m pretty sure the back can’t be steel because magnetic
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It’s not right against the magnets or stators/coils, so there should be little to no losses.
Need that 10K Mile Motor! 
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If I had access to a machine shop right now, I’d bang out a prototype right now
My experience maching the aluminum/case-hardened-steel interface where the can/rotor meets the axle/shaft is that it’s crazy how soft the aluminum is compared to the case-hardened steel axle. It’s nigh impossible to keep the cutting bit from walking off into the aluminum can (though it can be done)
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Yup. In the hierarchy of materials, aluminum is only a couple steps up from dirt.
Human flesh
plastic
aluminum
mild steel
tool steel
HSS
carbide
diamond
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Not entirely correct.
HK SK8 and Trampa motors use a key to secure the can to the axle.
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These motors need redesigning
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You have photos? Have seen it? @taz
If you have steel against aluminum. If the end cap bolts fail then the aluminum rotor will get eaten by the keyway. There’s not much thickness in the motor really.
Unless, you’re referring to a different size keyway than a standard 3x3.
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Not only that, but even with a key, that doesn’t stop the shaft from wobbling out the bore. Keeps things from spinning sure, but doesn’t help with the other axes.
Yes. I had trampa motors and currently have SK8 motors.
I am at work so can’t take pictures right now but I will take some when I get home.
It is the standard 3x3 key and there are zero problems with the key eating through the aluminium can. There is quite a bit of material on the end nub.
Apart from the key there are also 1 or 2 (can’t remember for sure) screws holding everything in place.
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Nah fuck that. Not touching motors 
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