Dogbone bent!

[Bobby Shaftoe]

My project truck has just hit its first stumbling block. The rear dogbone I
was planning to reuse in the transmission has just been extracted from the
rear suspension and is bent. The other one is broken (prompting me starting
the project earlier than planned). The bend is very near the ball end and
is not major (about 20 degrees at a guess) but will be enough to vibrate the
truck to death when migrated from the drive shaft (about 2,500 rpm) to the
transmission (about 11,500 rpm). I know these shafts are hardened steel so
my question is: Can I, as a hobbyist engineer, recondition this drive shaft
with the normal household and hobbyist tools?

My thinking at the moment is to put the main shaft in a vice, heat the bent
shaft in a gas hob flame and grasp with a pair of pliers and bend back to
straight. I have nothing to lose by trying it as I shall throw this dogbone
away if I have to buy a replacement.

There are a couple of things I don't know. Can I get enough heat out of a
gas hob flame to get the shaft to a temperature where I will be able to bend
it straight? Are there visual clues as to when I have hit the right
temperature (e.g. orange hot, red hot etc) because the last thing I want to
do is melt the shaft properly!

Now, from my vague recollections of metallurgy I can reharden the steel by
heating it up (as above) and letting it cool naturally. Is this the right
way round? Should I cool it quickly instead?

Thanks in advance for your help,
Bobby

[Dre]

I've straightened heaps of dogbones, I normally just stick them in a vice
(as high up near the bend as I can, all of mine have allways bent right near
the ball), then gently tap the end with a small hammer until its straight.
Then I put the axle into my lathe and check. Normally only takes me one or
2 goes with the PAT* and its done.

I originally thought that doing this would weaken the axle, but I haven't as
yet broken one. So all good thus far.

HTH

Cheers Andreas

*Precision Alignment Tool :)

"Bobby Shaftoe" <NObobbySPAMsPLEASE@softhome.net> wrote in message
news:cDdOc.1273$tW2.804@newsfe1-gui.ntli.net...
> My project truck has just hit its first stumbling block. The rear dogbone
I
> was planning to reuse in the transmission has just been extracted from the
> rear suspension and is bent. The other one is broken (prompting me
starting
> the project earlier than planned). The bend is very near the ball end and
> is not major (about 20 degrees at a guess) but will be enough to vibrate
the
> truck to death when migrated from the drive shaft (about 2,500 rpm) to the
> transmission (about 11,500 rpm). I know these shafts are hardened steel
so
> my question is: Can I, as a hobbyist engineer, recondition this drive
shaft
> with the normal household and hobbyist tools?
>
> My thinking at the moment is to put the main shaft in a vice, heat the
bent
> shaft in a gas hob flame and grasp with a pair of pliers and bend back to
> straight. I have nothing to lose by trying it as I shall throw this
dogbone
> away if I have to buy a replacement.
>
> There are a couple of things I don't know. Can I get enough heat out of a
> gas hob flame to get the shaft to a temperature where I will be able to
bend
> it straight? Are there visual clues as to when I have hit the right
> temperature (e.g. orange hot, red hot etc) because the last thing I want
to
> do is melt the shaft properly!
>
> Now, from my vague recollections of metallurgy I can reharden the steel by
> heating it up (as above) and letting it cool naturally. Is this the right
> way round? Should I cool it quickly instead?
>
> Thanks in advance for your help,
> Bobby
>
>

[Dan405]

"Dre" <ausjules1977@hotmail.com> wrote in message
news:2mtem3Fqn717U1@uni-berlin.de...
> I've straightened heaps of dogbones, I normally just stick them in a vice
> (as high up near the bend as I can, all of mine have allways bent right
near
> the ball), then gently tap the end with a small hammer until its straight.
> Then I put the axle into my lathe and check. Normally only takes me one
or
> 2 goes with the PAT* and its done.
>
> I originally thought that doing this would weaken the axle, but I haven't
as
> yet broken one. So all good thus far.
>
> HTH
>
> Cheers Andreas
>
> *Precision Alignment Tool :)
>

Seconded, if the bend is in the middle, just tighten the vice real hard on
it ;) I never bother heating them, just belt them straight.

--
Dan