Technical admissible concentricity defect on transmission shaft

Hi guys,
Today, I prepared my transmission shaft, narrowed to fit on my 32, before welding the 2 parts.
I've built a bracket, with bearings, to tune the concentricity. (see the pic)
After tuned it, the defect was 0.02-0.03 mm, that was really correct !
After made 3 welding points to maintain the 2 parts together, the defect was 0.15 mm.
Is that embarrassing for the shaft working ? And if no, for my information, what would be the max value to not overstep ?
Thanks !

 

We don`t speak metric

 

To be fare, he is in France . . . That's about .0059" you can probably try to draw it back straighter. With some strategically placed spot welds.

 

The rest of the world does know metric - so your 0,03mm is slightly more than 1 thou. Those 0,15mm are slightly less than 6 thou. You could alternate the welding to reduce the runout but I would not worry up to 0,25mm - if you balance the shaft it will be corrected with weight. If not, get is as good as possible -heat and quenching is your friend.

 

For the SAE folks:

0.15mm is 0.006".

Six-thousandths of an inch.

I've never seen an OEM driveshaft this good.

 

Spicer, a major manufacturer of drive line components says allowable tolerance for the ends is .010 and .015 in the center. Of course less is better.

 

Excellent home shop fixture! Welding without movement is an art form. Looks like the yoke is just tack welded, you could grind welds out and re weld. Use very small tack welds and check for concentricity as you go. Tack weld , second tack weld at 180 degrees and so on. Use a soft hammer to make minor adjustments as you go. I don’t think 0.15 mm is bad at all.
Good luck
Dan

 

Not knowing how to convert mm to inches here in the States is beyond me. Guy’s there are conversion charts available at your finger tips these days.

 

c'est bon!

 

1-inch is 2.54cm.

Or,

1-inch is 25.4mm.

 

1 mm is .03937 in.

 

Thanks Dan for that !
The yoke is just tack welded, yes, because my shaft is composed of 3 parts, the cut shaft, a machined sleeve which comes into the shaft tube and the yoke which comes into the sleeve, all these parts tack welded in the good position to have the good length. This waiting the final welding by a professional welder.
The yoke is well adjusted, I measure the defect on the sleeve which has a very slightly play into the shaft tube.

 

The concentricity is very good, the professional welder will know how to keep it straight.
By the way your English is very good.
Send us a photograph of your car.
Thank you
Dan

 

I think it means You parle francais
Dan

 

Thanks for your compliment !
I hope that the pro will know how to proceed to keep this good concentricity !!

 

C'est vrai, çà !

 

True for some but not all
Dan

 

Nice car what engine?
Dan

 

Ahhh, Olds powered!

 

I’ve never indicated any DS I’ve ever cut
Yours looks dang near perfect
Carry on

 

'66 Oldsmobile 330ci with Holley intake manifold and 2 weber DCNF carbs, hoping it works well !
Adaptor between carbs and intake manifold is home made with VW beetle valve covers !

 

Nice
Dan

 

That carburetion setup is very creative, well done!

 

Is your "Ahhh" a negative or positive one ?

 

Positive for sure, Olds engines are great engines!

 

That’s a different perspective LOL I’ve always understood Ahhh as positive Especially when****ociated with an vintage V8
Love this thread keep us posted
Thank you
Dan

 

Ask him ...

 

.02 mm works out to @ 0.000787402

in machinist terms that is about 7 tenths and change. I have worked to +/- .0005 on a govt project (making parts with part numbers that was all they would let me know) so I am gonna say 7 tenths is plenty close enough.

@elroots33 the driveshaft on my last 11 second streeter was about .003 0r @0.0762 off if I recall and it worked fine for at least 30K miles or 48280.32 KM. You are probably close enough.

 

Cool taillight / license frame combo.