I'm looking for the best steel for these motors I've been getting made:

steelhubs.com

 

they take a beating and I'd like to not have the shaft or housing deform which makes me think I'd want a high carbon steel, but they're electric motors and at least the outer housing will benefit from the lowest carbon content possible as it will have greater permeability and strengthen the magnetic field and make a stronger motor. From what I read there's not much that can  be done to 1018 to harden it though.  I'm assuming hardness is what I want most.  Presently doing both parts in cold 1018 and soon to have some in 1144 but I think they will be weak motors.  I'm not sure what's needed and maybe even the cold 1018 is good enough.  I don't have money to do testing or engineering and am hoping  someone here has some relative experience I could maybe extrapolate from

 

the lower the carbon content the better but also the easier to machine the better

 

thank you 

Not enough information.

Where are these motors being used, and how big are they..... 1/4hp or 20hp?

Don't confuse hardness with toughness, as they are two different things. A hammer is tough, but a file is much harder. Which one will take more of a beating??

1144 is a higher carbon content, but it is a screw machine stock with elements added to aid in machining. 

The motors are maybe one horsepower continuous.  Hard to say.  

I'm looking for whatever characteristics keep shaft and bearing housings from deforming.  The loads come from outside forces not the motor.  They come from riding over rough roads or getting run over by cars.  if you look at the website steelhubs.com you can see the motors inside and out and see some video of me riding around.   Skateboard hub motors 

Want to make the most robust thing I can but still have a rotor back iron with enough permeability to reflect the magnetic field from the magnets.   I imagine the shaft, since it's not moving and a smaller surface area, will take the hardest hits and I'd like to believe 1144 for that part and 1018 for the rotor will be good enough ( all bearings are 7mm diameter and u can see the shaft's other dimensions generally on the site)

any thoughts? 

I'm thinking you should be looking at nickel steels.  Nickel imparts toughness and fatigue resistance. 

I read the permalloy (nickel alloy w iron) is hard to machine though.   That's the other characteristic I'm looking for, easy to machine.  The 1018 and the 1144 are.  Maybe case hardening 1018 is worth doing.  Most of what I read says it's not worth doing as the carbon content is so low, but sometimes I read it absorbs the carbon around it and it is worth doing. 

Perhaps talking to your engineer would be a good starting place?

Who is my engineer?  Who would like to be my engineer?

although I have a site and sell things I don't make almost any money. Experimental. Learning while doing so I sell cheap.  The prices on the site aren't real and never sold for those prices. 

Dont have any of hose motors left.  Doing bigger motors, more powerful, run cooler, bigger sealed bearings. But I have two missing links...what materials would be best and how to get an interference fit done

You need an engineer if you have to outsource the work. I don't believe low carbon steel is going to do it for axles on skate trucks let alone for a drive shaft in one.

The right grades aren't that hard to machine till after heat treat. If you just wing the materials science you'd better have really good insurance.

Frosty The Lucky.

14 hours ago, Hummina said:

i don't have the money for much.  id like to find what the typical loads are on a skate axle are and knowing its only 8mm and what metal has sufficed for that purpose in the past I could figure what material my much larger shafts would need to be.   I need to do the engineering myself or find someone who can help for cheap at most 

When I first started I sold 120 with 6000 aluminum as the center and didn't hear of any problems with any of them.  I had one of my own run over by an suv even.  

There is no drive shaft on these.  No torque transmitted through a shaft.  The shafts are stationary and just need to be able to take the loads of the rider on a rough road.  

 

Quote

 

 

The smallest shaft is 20mmx7mm as apposed to an 8mm typical skate axle that also has a 7mm bearing..two per wheel. The latest version is 1144 steel.  Really all I need to do is figure the difference in load ability between the two steels and figure how the size will distribute or reduce that load.   Where would I go about finding an engineer who could help?

Maybe I could still use the 1018 for the rotor as its surface area which support the small bearing is much larger.  The smaller bearing sits in a 7x 32mm housing. 

Or...maybe i should get it case hardened

If u go to steelhubs.com u can see it all