It’s probably how they secure the axle in the machine that makes the axle. (likely a lathe)
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Found a fun new problem while i was in there:
Broken winding… fuuuuk
Interesting that I never had a performance problem with this motor though. Is it worth it to clean the varnish and solder back together?
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Hmm do you have the detection results from before taking apart? Then you can compare to after you resolder that broken winding.
I am still trying to figure out why there is no grub screw. What is locking the rotation of the can to axle?? Not just glue surely.
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Ok, here is the final, hard won truth. I scienced this motor, because SCIENCE.
There are two small M4 set screws hidden deep within the blue epoxy filling both holes in the can. The shaft has two unthreaded cavities to align with those set screws.
If you’re going to replace a shaft in the latest gen Flipsky motors, I recommend drilling both holes out with a 7/64" (or 3mm) drill bit. There’s the outer plug, a gap, and then an interior plug on top of the set screw. You’ll know when you’ve hit the set screw - be gentle. Should take a 2mm hex key. You may have to dig out chunks of epoxy to get the hex key to bite.
Or, you can be like me and put the entire can under a hydraulic press.
Don’t be like me.
Now… after I check this steel shaft for straightness (which it most likely is still perfectly good), should I fill the aluminum can shaft hole with JBWeld and use a drill press to create a new, tighter mounting hole? Or see what high strength retaining compound can do instead?
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Never trust adhesives.
Go for the epoxy
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Is there a more permanent epoxy than JBWeld?
There are lots of different epoxies. JB Weld is a very hard epoxy. West System 650 would be the opposite of that. Both are hard, but JB Weld 8265 Original Steel is hard hard, like metal, you can drill and tap it and bolt to it. WS 650 is hard but not brittle hard. JB Weld 8265 can be cracked.
And then you have a bunch of other epoxies that are between those two, and then probably a million epoxies I have never even used.
If you only want to buy one, I’d get West System 105 + 206 OR Silvertip Epoxy, they are great all-purpose epoxies IMHO
For a rotor to shaft bond I would probably want a hard epoxy so it was less likely to work its way crooked.
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Make sure you clean the surface very well and even sand it lightly to ensure there are no oils on it.
And always, ALWAYS mix exactly according to directions. Exactly. Including stir time and everything.
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Ok, another option I was thinking about last night -
- Get a 10mm aluminum round bar, ideally oversized.
- Cut to length and epoxy into the hole.
- Clean up / face the end.
- Find the can center point (this will be the hard part)
- Drill press new hole, slight interference fit
- (Optional) drill out old set screw holes and tap one size larger
- Freeze old shaft
- Install shaft, epoxy in place (epoxy + cold may not work, but need some way to fix rotation, tbd)
This all basically amounts to an aluminum sleeve vs only epoxy. Which I like slightly better.
I was half right
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