Re-winding a hubmotor
- Thread starter Farfle
- Start date
Farfle
100 kW
Thanks mate, ill get it terminated and then press the axle in.
liveforphysics
100 TW
That is so beautiful Farfle. My fingers have sympathy pains for you just looking at it.
You should be really proud of yourself, and I'm proud of you too. That offer to come dyno tune for free still stands of course.
I would like to recommend that before buttoning it all up or varnishing the wingdings (if you choose to), that you assemble the magnet rotor in place and give it a spin. We ran into a few problems where windings looked fantastic, but had one tooth a turn short in parallel with one that doesn't, and it makes the thing spin like its filled with peanut butter, and it dumps all that extra power into heating the mis-matched turn paralleled teeth.
Hopefully she's got no issues at all, but just incase, it's worth the pre-check rotor spin before locking it all down IMHO.
Can't wait to see it run! Such a great execution of a great idea! Woot!
You should be really proud of yourself, and I'm proud of you too. That offer to come dyno tune for free still stands of course.
I would like to recommend that before buttoning it all up or varnishing the wingdings (if you choose to), that you assemble the magnet rotor in place and give it a spin. We ran into a few problems where windings looked fantastic, but had one tooth a turn short in parallel with one that doesn't, and it makes the thing spin like its filled with peanut butter, and it dumps all that extra power into heating the mis-matched turn paralleled teeth.
Hopefully she's got no issues at all, but just incase, it's worth the pre-check rotor spin before locking it all down IMHO.
Can't wait to see it run! Such a great execution of a great idea! Woot!
StudEbiker
100 kW
Farfle said:
Drool.......
liveforphysics
100 TW
One more little thing before you button her up. 
Make sure those attachments for lengthening the wire I see in a few places are done with a crimp and not solder. Or if it is done with solder, make sure it's some very high temperature stuff, it's really lame to have motor failures from solder joints letting go while everything else is still OK.
Make sure those attachments for lengthening the wire I see in a few places are done with a crimp and not solder. Or if it is done with solder, make sure it's some very high temperature stuff, it's really lame to have motor failures from solder joints letting go while everything else is still OK.
Alan B
100 GW
Nice Job!
Farfle
100 kW
The little yellow guys are actually sleeves of insulation from some 200c turnigy wire, I soldered then with 3% silver 97% thin Sypher which iirc melts at a higher temp.
Harold in CR
100 kW
What a nice looking job you did. I have a Crystalyte to wind, and have questions, but, will ask them at a later time. Waiting to see the results of all that hard work. 8) 8) 8)
Farfle
100 kW
Got the axle finished, 4340 is hard to machine!
nicobie
100 MW
Nice job!
Can't wait to see it run.
Can't wait to see it run.
Farfle
100 kW
BLAM!!, DOH!
Cause of failure, press OD too big for axle ID :lol: :lol: . it was almost there too!
Cause of failure, press OD too big for axle ID :lol: :lol: . it was almost there too!
Farfle
100 kW
And now I cant get it off the dang press... WTF!
FastDemise
100 W
A little duct tape and you'll barely notice it.
Totally sucks man. You were so close.
Totally sucks man. You were so close.
Farfle
100 kW
Andje said:O man, that sucks, but is also hilarious. This motor really likes to catastrophically shatter on you
If these dang parts would stop breaking I would have two of these motors... interesting how it failed tho, 4340 is an interesting alloy.
Farfle
100 kW
well, the sawzall didn't want to cut it, so time to break out the mighty dremel!
liveforphysics
100 TW
Damn! That sucks!
I remember I started with 4340 for my custom motor shafts in my first ebike, and then went to 4330 after putting up a bunch of crap from the 4340.
I remember I started with 4340 for my custom motor shafts in my first ebike, and then went to 4330 after putting up a bunch of crap from the 4340.
Farfle
100 kW
what advantages does 4330 have over 4340? im not making another axle out of 4340, its strong as hell, but its a a PITA to machine.
bigmoose
1 MW
Hang in there! The winding is a work of art! This project is starting to get a character of it's own however.... "When FROK Motors Go Bad..." comes to mind. One might think this dual FROK does not wish to be born! 
Edit:I just showed my wife this thread... her reaction, was "Moose you thought you had bad luck..." "It's stuck on the press .... You got to be kidding me..."
Edit:I just showed my wife this thread... her reaction, was "Moose you thought you had bad luck..." "It's stuck on the press .... You got to be kidding me..."
liveforphysics
100 TW
Farfle said:
I think temper has as much or more of a factor than the alloy between the two, but the 4330 cuts with a shiny finish rather than a rough chattery surface, and it cuts smoothly and controlled, throwing up big long chips rather than exploding off little chunks of rice sized pieces like I encountered with the 4340.
Rigidity of the machine has a massive impact on the cut quality when alloys get really hard.
Bigmoose could help you a lot more than I can, he has more experience with this stuff in his pinky than I've got in my lifetime.
Farfle
100 kW
Ill call around and see if any of the local shops have any 4330, I didn't have too many problems with the finish, it was just picky about the tool, the carbide left an awful galled-looking finish, but cut great, so I roughed it with that and finished it with a nice sharp HSS tool. the biggest problem with the 4340 was drilling it, I had to re-sharpen the bit a few times (3/4" HF POS) and slow things waaaaay down to make it thru, Spinning at 340 rpm and feeding by hand burned the bit really bad. I ended up running it at 135 rpm and feeding at .018"/rev with the auto feed.
bigmoose
1 MW
Luke, I was wondering about the axle material choice also. I typically have used Stressproof for axles and shafts in rotating machinery. Machines like butter and is 115Ksi Tensile and 100Ksi Yield off the truck.
The 4330 looks like (for class A) 130Ksi Tensile and 115Ksi Yield annealed.
The 4340 is around 161Ksi Tensile but only 103Ksi Yield annealed.
I might be missing something...
The 4330 looks like (for class A) 130Ksi Tensile and 115Ksi Yield annealed.
The 4340 is around 161Ksi Tensile but only 103Ksi Yield annealed.
I might be missing something...
liveforphysics
100 TW
Farfle said:
Flow tons of coolant onto that bit. Take a little hand oil pump and just squirt your heart out while taking an aggressive cut. Thick chips generally make for cool tools, right up to the point where you're snapping the bit. (at least in my very crude amateur experience)
StudEbiker
100 kW
You might try an angle grinder instead of a Dremel. I have used one to cut hardened steel when a drill wouldn't do anything.
Farfle
100 kW
I ended up getting it off with a hammer, and pressing it back out the other side. Im going to grab a piece of 1144 stress proof rod and make another one tomorrow.
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