What do you reckon CRF axles are made of.

[EnglertRacing]

What's your best guess on what Honda CRF axles are made of?

[The Inquisitor]

Steel

[EnglertRacing]

7 minutes ago, filterx said:

Steel

No, I I thought they were made out of compressed belly button lint. I guess I should have been more specific I need to  machine a custom axle. I'm curious what the stock axle might be made from.

[The Inquisitor]

Sorry just stuck a magnetic on mine and its steel.

Now as to what TYPE of steel its made out of is beyond me but this might help.

http://www.practicalmachinist.com/vb/general-archive/what-type-steel-motorcycle-axle-79912/

or even this which is somewhat obvious

https://www.google.ca/?gws_rd=ssl#q=what+type+of+steel+is+a+drit+bike+axle+made+of

And I'm slightly jealous that you have the shop/tools etc to machine your own axle ?

 

[SDet]

You're going about this backwards. You'd be better off figuring out the loads and deciding on a material from that than just copying the factory. 

 

Depending on how it was originally made, you might not be able to get the same strength with the same material. 

 

Say it's forged with rolled threads and you turn it with cut threads, the oe will be stronger. 

 

That said, I like stainless, and probably done, the friction between the spacers and swingarm support the load and the axle only supplies tension. 

[EnglertRacing]

14 hours ago, filterx said:

Sorry just stuck a magnetic on mine and its steel.

Now as to what TYPE of steel its made out of is beyond me but this might help.

http://www.practicalmachinist.com/vb/general-archive/what-type-steel-motorcycle-axle-79912/

or even this which is somewhat obvious

https://www.google.ca/?gws_rd=ssl#q=what+type+of+steel+is+a+drit+bike+axle+made+of

And I'm slightly jealous that you have the shop/tools etc to machine your own axle ?

 

here is a steering stem I made from 7075 aluminum to put 1986 kx 80 tripples on a 1980 cr80

[EnglertRacing]

2 hours ago, SDet said:

You're going about this backwards. You'd be better off figuring out the loads and deciding on a material from that than just copying the factory. 

 

Depending on how it was originally made, you might not be able to get the same strength with the same material. 

 

Say it's forged with rolled threads and you turn it with cut threads, the oe will be stronger. 

 

That said, I like stainless, and probably done, the friction between the spacers and swingarm support the load and the axle only supplies tension. 

Front axle.

I've not got the slightest idea in how to calculate the many loads the front axle sees. 

reklues uses a little baby stainliess axle

Been trying to get my hands on a rekluse e axle for years now.

got one on ebay for a yam, to put in my Honda, could have made it with new wheel spacers but its bent.

So i'm going to send it back and make something a little better/stronger.

I'm wondering what the Honda axles are because i want something a bit stronger than that as I am going Down in diameter

 

I also like stainless.

but i was thinking 4130 or 4140 as well

I don't want it to be too hard/brittle.

[SDet]

Well, from the torque spec you can get the tension, that'll be the minimum strength. But you probably want a safety factor of some sort. So, do the tension over the cross sectional area to get the stress. 

 

From there you can look at di materials and different dimensions and see what has a high enough safety factor for your liking. 

[bikedude987]

4130/4140 would be a good choice, then just copy the factory dimensions.  When in doubt, increase the wall thickness (smaller bore through the center) to add some strength.  

If you want to go stainless, I recommend something in the 400 series.  300 series, especially 303, is pretty easily bent.  

[EnglertRacing]

1 hour ago, bikedude987 said:

4130/4140 would be a good choice, then just copy the factory dimensions.  When in doubt, increase the wall thickness (smaller bore through the center) to add some strength.  

If you want to go stainless, I recommend something in the 400 series.  300 series, especially 303, is pretty easily bent.  

Unfortunately I'm reducing the outside diameter 7mm ish, to create an offset design similar to the recluse e axle,  sounds terrible right?, well the e axle hasn't killed anyone that I know of, but the one that I bought is bent.  So I'm going to duplicate it with an eye towards strength I'm going to integrate the 20mm (brake side) eccentric to be part of the shaft rather than slide on, which will allow me to run a much larger axle than the recluse, and still get more eccentric.  

 

All that being said....

I think I need something stronger, and tougher than stock as I'm reducing the diameter.

I just don't want something so hard that it breaks instead of bending....

You have a much much worse day if it brakes......

[bikedude987]

If I were you, I would be looking at something like 440c and hardening it post machining (unless you can machine hard).  Temper back down to HRC 45-50 to maintain some toughness.

If you do something that can shatter that axle you have MUCH worse problems.  

But, you're in uncharted territory, especially if you can't do the calculations (they're not super easy except for 'idealized' situations.  

Start with something like thishttps://www.mcmaster.com/#standard-stainless-steel-rods/=18o4bw1  and skip the hardening.  If you bend it, start hardening the next one.

OOooooooR

make a set of offset triple clamps like everyone else and use the stock axle.  That's all the e-axle is doing anyway...

[EnglertRacing]

19 minutes ago, bikedude987 said:

If I were you, I would be looking at something like 440c and hardening it post machining (unless you can machine hard).  Temper back down to HRC 45-50 to maintain some toughness.

If you do something that can shatter that axle you have MUCH worse problems.  

But, you're in uncharted territory, especially if you can't do the calculations (they're not super easy except for 'idealized' situations.  

Start with something like thishttps://www.mcmaster.com/#standard-stainless-steel-rods/=18o4bw1  and skip the hardening.  If you bend it, start hardening the next one.

OOooooooR

make a set of offset triple clamps like everyone else and use the stock axle.  That's all the e-axle is doing anyway...

yeah,

i kinda whish i could get hold of the guy that did the e axles, ask him what material/heat treat he used, and just go larger diameter.....

but even rekluse hasn't heard anything from him....

cant change triples just to check what offset i like.....

mine are already um special.....

I just want to back to back test more and less trail to see if I've got it right, or if i can achieve the feel i'm after....

If i find that i like much more or less offset, yes i will do different triples.... because i really don't like the smaller axle business, and the flexing that it will bring.

its mostly just an experiment in steering geometry so i can learn whats what with the feedback from the contact patch to my hands....

 

 

 

[EnglertRacing]

well thank you google

"The Rekluse e-Axle is an eccentric axle assembly which replaces the stock front wheel axle. The e-Axle allows the rider to instantly tune the steering characteristics of their motorcycle to meet changing riding conditions. Within minutes the rider may adjust the e-Axle over a 4 millimeter range, achieving instant trail adjustment without the cost and hassle of offset triple clamps. There is no perfect offset for every rider or every riding condition. Only the eAxle makes it possible to instantly adjust and utilize the best offset for every riding condition. The Rekluse e-Axle is made of heat-treated, precision ground 17-4PH solid stainless steel and despite the smaller diameter is designed to provide greater strength than the stock axle. So ride your e-Axle everywhere and have the ability to adjust to unexpected changes in riding conditions."

 

[bikedude987]

FYI 17-4 is a type of precipitation hardening 440c stainless.  

[CDNSXV]

On 7/24/2017 at 6:48 PM, EnglertRacing said:

No, I I thought they were made out of compressed belly button lint. I guess I should have been more specific I need to  machine a custom axle. I'm curious what the stock axle might be made from.

Most likely some kind of chromoly steel.  It is cheaper than stainless and stronger too.

I'd have no issues going to a stainless though.  Look closely at your stock axle and it will have some kind of phosphate? surface coating to prevent corrosion.  With stainless you won't need that.

I'm not up on all the shear specs for various SS but I'd prob look at 17-4ph as it is reasonably easy to get, not overly spendy and easy to turn.  I've done a bunch of work with 316 and a few other 300 series SS and they can be a bit more difficult to turn.  Getting a decent surface finish is going to be important and 17-4 is good for that.

[CDNSXV]

On 7/24/2017 at 6:55 PM, filterx said:

https://www.google.ca/?gws_rd=ssl#q=what+type+of+steel+is+a+drit+bike+axle+made+of

And I'm slightly jealous that you have the shop/tools etc to machine your own axle ?

 

I've got my own home machine shop.   14-40 lathe and a knee mill, both with magnetic DRO's.  

It is really nice to be able to machine up small parts and fix small problems or make improvements to parts.  I am currently designing a set of fully sealed and shielded wheel spacers.  I discovered there is nothing stopping water and mud from travelling between the axle and spacers right into the wheel bearings.  Turns out the bearing dust seals only seal between the hub and the spacer.

[SDet]

3 hours ago, CDNSXV said:

Most likely some kind of chromoly steel.  It is cheaper than stainless and stronger too.

I'd have no issues going to a stainless though.  Look closely at your stock axle and it will have some kind of phosphate? surface coating to prevent corrosion.  With stainless you won't need that.

I'm not up on all the shear specs for various SS but I'd prob look at 17-4ph as it is reasonably easy to get, not overly spendy and easy to turn.  I've done a bunch of work with 316 and a few other 300 series SS and they can be a bit more difficult to turn.  Getting a decent surface finish is going to be important and 17-4 is good for that.

And 17-4 is so easy to harden. 

[CDNSXV]

My only issue with hardening parts is that it takes a lot of experience to know what you are doing and it is way too easy to over harden a part and make it overly brittle.

[SDet]

17-4 is so easy, find the ak steel spec sheet for 17-4 and find an oven that'll do 1k. H900 is very strong, but will still bend a lot before breaking. It's also not terrible to machine, and gives a better finish than annealed. 

[EnglertRacing]

I dropped it at my mold maker friends house.

he took it to work to test it on his rockwell tester thingy mo bob.

he told he its not hardened its just plain ol 17-4