Pressing out an axle on a hub motor for replacement

[Affliction]

I had the honour tonight of assisting on warranty work for stripped axle threads on a newer chrystalite 408 hub motor.
The dealer was provided a replacement axle and instructions from the vendor and needed my shop press to complete the task.
Now the instructions were to just lay the stator flat on the windings and press away........
We were assured it was done this way all the time. So we did as we were told to do despite our reservations.
The aluminum stator cracked but not enough to destroy it. What a dumb ass way to press a axle out
We proceeded to press the new axle in, (like we were told to do on the end of the axle threads) and the new axle went in bent like a bannana on the threads! What kind of clown show is this? We did start the splines before pressing with lots of lubrication.
So now we're left with a bent axle and an axle with stripped threads.
Now for the right way We pressed out the new axle and then rethreaded the old axle and pressed it back in with proper arbors to support the stator.
We could have saved all this bullshit by just rethreading the axle coarser to begin with without taking the motor apart!
Why go to all this effort to replace a stripped axle with an equally shitty design? As it is the vendor owes for labour and shop time and proper replacement axle nuts.

 

[spinningmagnets]

Design engineers often either don't care, or if they do care, their bosses don't allow them to design a "slightly" more complex/expensive interface to make repair/maintenance easier. Plus the boss may "believe" if he makes stripped axles easier to replace, perhaps he will sell fewer replecement hubmotors.

Since aluminum expands from heat more than a steel axle, perhaps heating the hub/axle joint slightly might lessen the grip (gently, not enough heat to melt or damage anything). Perhaps a heat-gun rather than a torch?

Once I needed to remove the wheel lug-studs from a front drum brake on a 1963 Ford Falcon to install longer ones. I took the drum off, and put the lugnuts on the tip of the studs so the sledgehammer wouldn't mushroom the lug tips. Tapped on the lugs "just enough" to break them loose...The lug-studs were banana shaped and the drum face was "dished". Later I found an auto machine shop that said they press out/in the broken/new studs all the time (with the proper fixture) for $5 a stud.

 

[Affliction]

Since aluminum expands from heat more than a steel axle, perhaps heating the hub/axle joint slightly might lessen the grip (gently, not enough heat to melt or damage anything). Perhaps a heat-gun rather than a torch?

The axle splines are not on aluminum, there is a steel collar casted into the aluminum stator that the axle actually splines into.
You can't use heat at all here, the phase wires are too close and will burn and short out.
I have photo's of this exercise, just need a bit to sort through them and upload for post.

 

[DasDouble]

Can you do this too with an QS motor? My axle did just broke and now I need a new one.......

 

[series_hybrid]

Broken Axle

In this instance, it "looks like" the torque-arm was made from a weak softer steel, and the axle twisted the straight slot into a "figure 8" shape (see the red circle).



This pic is used with permission of Facebook user https://www.facebook.com/groups/222291591463603/user/100089186447125/

 

[Chalo]

Ideally it would make sense to use material of similar strength and hardness for the torque arm as for the axle. But if they differ, it's definitely better to use a softer material for the TA. Replacing one of those is no big deal compared to replacing the axle.

In the photo you posted, it seems both axle geometry and torque arm thickness were less than optimal.