1018 steel shaft strong enough
1018 steel shaft strong enough
(OP)
skateboard.
the design is solid and I havent had any problems with the shaft deforming with even the aluminum version I was selling before, but knowing a standard skate axle is made of a much harder steel I'm concerned things will deteriorate. I havent put enough rough miles on them to know for sure and would like to find out what I should be doing instead of testing till destruction.
there are two shafts and housings per motor, the bigger shaft is 42 x 7mm and the smaller is only 20x7. fitting a 42x50x7 and a 20x32x7 bearing. high heat retaining fluid and bearings have c3 internal clearnace since the motors get hot. 1018 steel with an "electroplate" finish which I need to find out what it is too.
dont want deformed shafts!! how do you think things will go? Maybe there's another similarly easily machined steel that will be stronger or can strengthened..although the mild steel does work great in the rotor as a flux ring and retains the magnetic field very well.
thank you
john
the design is solid and I havent had any problems with the shaft deforming with even the aluminum version I was selling before, but knowing a standard skate axle is made of a much harder steel I'm concerned things will deteriorate. I havent put enough rough miles on them to know for sure and would like to find out what I should be doing instead of testing till destruction.
there are two shafts and housings per motor, the bigger shaft is 42 x 7mm and the smaller is only 20x7. fitting a 42x50x7 and a 20x32x7 bearing. high heat retaining fluid and bearings have c3 internal clearnace since the motors get hot. 1018 steel with an "electroplate" finish which I need to find out what it is too.
dont want deformed shafts!! how do you think things will go? Maybe there's another similarly easily machined steel that will be stronger or can strengthened..although the mild steel does work great in the rotor as a flux ring and retains the magnetic field very well.
thank you
john





RE: 1018 steel shaft strong enough
RE: 1018 steel shaft strong enough
I've been involved in projects that approach it from both ends - design the product completely and determine expected lifetime on the back end, or determine the required lifetime and engineer the product to meet that requirement. You need to choose which is appropriate in your circumstance.
It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.
RE: 1018 steel shaft strong enough
I do t sell the aluminum anymore Beckie of thermal expansion and now just the 1018 stell but wonder if a harder steel would be better ?
If u look at my website u can see the shaft is part of an electric motor, so must be precision, and also very strong as it also bears the loads of the skate wheel. Very important it doesn't deform
RE: 1018 steel shaft strong enough
Consider whether a few cents saved for raw material of this component is worth the potential financial liability cost from someone injured as the result of this component failing due to weak material.
RE: 1018 steel shaft strong enough
Do you think the structural integrity and wear resistance might be compromised for this application in using a resulfurized free-machining 1144 steel?
RE: 1018 steel shaft strong enough
RE: 1018 steel shaft strong enough
Choice for some reason?
RE: 1018 steel shaft strong enough
RE: 1018 steel shaft strong enough
RE: 1018 steel shaft strong enough
RE: 1018 steel shaft strong enough
1) You make several references to magnetic properties of the various steels, implying this is an important consideration. However, you also state that you have used aluminum in the past. Aluminum is non-magnetic so if that worked I can't imagine how the magnetic properties of the steels can have any bearing on the design.
2) You don't say anything about the processing of the 1018 that you are using. Is it cold finished? Do you heat threat it? Both of these and other factors will affect the strength. Most alloy steels gain significant strength from heat treating.
It sounds like you are not yielding or fracturing the shafts so one can possibly conclude that the yield strength and toughness are acceptable. It sounds like you are concerned about fatigue strength. First you will need to do a stress analysis of the shafts, from that you can do a fatigue analysis. The good news is that most steels have a well defined fatigue limit so if you keep your stresses under that the life is practically infinite. That is a gross over simplification of a subject that fills many books.
Lastly, it looks like these wheels just bolt onto standard skate board trucks. The axles on those trucks are much smaller diameter (1/4"?) and appear to be more highly loaded than your shafts. When you do the stress analysis of the shafts it would not be too much more work to analyze the axles too for comparison. Do you know what material the axles are?
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The Help for this program was created in Windows Help format, which depends on a feature that isn't included in this version of Windows.
RE: 1018 steel shaft strong enough
From what I read 1018 doesn't benefit much from any treatments but I'll look again
These motors just screw and glue in a regular 8mm skate axle. The steel used for those :
http://www.eng-tips.com/viewthread.cfm?qid=327719
The new design I'm getting done is longer and the manufacturer is going to do just one to see if they can do it. Why it's harder I don't know the details but if u see my site steelhubs.com the new design will be the same almost except almost twice as long.
Thanks for all your help with this I'd be blind otherwise
RE: 1018 steel shaft strong enough
RE: 1018 steel shaft strong enough
now...to figure out how to do the slightest interference shrink fit. next time.
RE: 1018 steel shaft strong enough
That's why it's called Engineering and not Guessing.
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The Help for this program was created in Windows Help format, which depends on a feature that isn't included in this version of Windows.
RE: 1018 steel shaft strong enough