How straight are our axles?

[shiftpro]

Familiar story? Is there a recent thread on this subject?
I agree with the inertia theory. Or, some kind of engineering math where it gets straight with heat??

No not here Shaker... sorry I can't remember where I've heard this discussion.

 

[Vbb199]

Chuck it up with a live center and turn it on at 1500 rpms , observe the effect it has

 

[Turbo4whl]

A quarter mile drag racer once told me, when you put your new semi floating axles in, paint a line down the length. Then you can see how much they have twisted. He said they will twist a full turn before they fail. This way you can replace them before they shear off.

I agree with @idahovette that horse power applied more than once will cause the bow when it twists.

 

[dvdswan]

So, do me a favor since you have a lathe. Attach one side of the axle to the lathe and leave the other unattached. See how much runout there is.

I understand both sides are supported, one by the carrier and the other by the axle bearing. But a bent axle will eventually start wearing parts prematurely.

 

[Vbb199]

A quarter mile drag racer once told me, when you put your new semi floating axles in, paint a line down the length. Then you can see how much they have twisted. He said they will twist a full turn before they fail. This way you can replace them before they shear off.

I agree with @idahovette that horse power applied more than once will cause the bow when it twists.

Basic physics/engineering, if there was no molecular allowance for twist, it would just explode when torque was applied, kinda the same thing as large, tall buildings/structures being allowed to sway in the wind slightly

That'd be a reason they build axle shafts/ tranny shafts/etc out of 4140 and such, vs hardened toolsteel lol , toolsteel would just give slightly then explode....

Good ol OEM cast iron can twist a bit before it busts tho.

 

[Vbb199]

So, do me a favor since you have a lathe. Attach one side of the axle to the lathe and leave the other unattached. See how much runout there is.

I understand both sides are supported, one by the carrier and the other by the axle bearing. But a bent axle will eventually start wearing parts prematurely.

That type of experiment i dont think would be accurate tho? Idk

The 2nd end wouldnt be contained to a "range/field", meaning the smallest change in motion would quickly cause it to spiral out of control and launch out of the lathe into our poor friends face

 

[Turbo4whl]

That type of experiment i dont think would be accurate tho? Idk

The 2nd end wouldnt be contained to a "range/field", meaning the smallest change in motion would quickly cause it to spiral out of control and launch out of the lathe into our poor friends face

I agree! Would be worse than leaving the key in the chuck.

 

[dvdswan]

I'm not a lathe expert so it was just a guess. It seemed logical.

 

[idahovette]

@Turbo4whl , we used to paint he lines on the axles and check 'em after a days race. If they had a half twist or more we replaced them. Old Tri-five 3 speed transmission output shafts always went a turn or so before they broke, right in front of the yoke.

 

[wanderinthru]

So, do me a favor since you have a lathe. Attach one side of the axle to the lathe and leave the other unattached. See how much runout there is.

I understand both sides are supported, one by the carrier and the other by the axle bearing. But a bent axle will eventually start wearing parts prematurely.

Interesting result

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You can see what I did, realize there is some sag introduced sticking out like that but? It was .034 on the machined surface by the wheel bearing, .037 then .034 headed tword the chuck on the ground(?) surfaces. Interesting part is, like talked about eariler, the highs and lows are not in line, so it is in fact twisted. There is all the info I have, and more than I know what to do with? Had about a .002 in the last pic next to the splines on a machined surface. Know the indicator set up isn't ideal but the best I could do with my lack of fore though when I chucked it.

@Vbb199 have you ever turned one of these things? The one I did sure didn't act like 4140. Or any type of cast iron or maluiable(sp?) steel. Turned more like a cheap grade 2 bolt, didn't cut, just pulled apart. It actually broke when I was parting it off, with a good 1/2 inch still intact.

 

[wanderinthru]

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To add to the confusion. The straight lines are the lows, the arrows the highs.

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[Vbb199]

Interesting result

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You can see what I did, realize there is some sag introduced sticking out like that but? It was .034 on the machined surface by the wheel bearing, .037 then .034 headed tword the chuck on the ground(?) surfaces. Interesting part is, like talked about eariler, the highs and lows are not in line, so it is in fact twisted. There is all the info I have, and more than I know what to do with? Had about a .002 in the last pic next to the splines on a machined surface. Know the indicator set up isn't ideal but the best I could do with my lack of fore though when I chucked it.

@Vbb199 have you ever turned one of these things? The one I did sure didn't act like 4140. Or any type of cast iron or maluiable(sp?) steel. Turned more like a cheap grade 2 bolt, didn't cut, just pulled apart. It actually broke when I was parting it off, with a good 1/2 inch still intact.

I honestly am not sure, i ponder if that axle shaft is just made of cast steel or some ****?


I know the older goods are made of cast iron....
And as far as what i meant by 4140, the aftermarket products are usually made of the default 4140PH

 

[Craig Nedrow]

Machinist handbook states that axle steel is 1050, aftermarket uses many types of metal, 4130, 4140 1550 etc. On Bonneville, stock cars, we used to turn the axle the whole length as a way to balance the centrifugal forces as RPM increased. These axles were usually the same or larger then the splines. I have used Strange on all my axle, rearend stuff, check them out: https://www.strangeengineering.net/

 

[Vbb199]

Machinist handbook states that axle steel is 1050, aftermarket uses many types of metal, 4130, 4140 1550 etc. On Bonneville, stock cars, we used to turn the axle the whole length as a way to balance the centrifugal forces as RPM increased. These axles were usually the same or larger then the splines. I have used Strange on all my axle, rearend stuff, check them out: https://www.strangeengineering.net/

Thats the guys (or moser) im gonna buy shafts from for my 12 bolt in my c10 whenever the big block twists them in half. (Or explodes the carrier) whichever comes first.

 

[Craig Nedrow]

Thats the guys (or moser) im gonna buy shafts from for my 12 bolt in my c10 whenever the big block twists them in half. (Or explodes the carrier) whichever comes first.

Check out the SS axles, have some in a D60, bullet proof.