Tail and Intermediate shaft coupling bolts

[vs1973]

Hello All,

I would like your advice. What is the tolerance of fit between bolt and hole (dia:48mm) for flange coupling between tail and intermediate shaft?

I've checked the drawings and ANSI and I found differnet values.

Is it permited for cooling fitted bolts to be smaller 1/100mm from the hole?

Do you have any other records for similar or bigger couplings?

 

[MikeHalloran]

I don't understand what ANSI would have to say about fits in a particular manufactured product

...

which you haven't actually identified for us, so we can't be of much help

...

except to say that if you have a drawing that tells you what you are asking about, why would you consult another source?



Mike Halloran
Pembroke Pines, FL, USA

 

[vs1973]

Dear Mike,

According maker the fit is an interefernce fit.

So I found the intereference fit standard values from ANSI which are different than the drawing values. Also maker measurements are within the standard but when we receive the shafts and bolts and we carried out our measurements we found different values which are out of standards of course.

In addition maker's letters on this matter are not clear. First letter says that the have changed the tolerance, second that is acceptable and you did mistake during measurements. Our measurements are 100% correct and I verify during fit of bolts. Bolts were going very easy inside hole.

I wrote that the bolts are used for coupling between tail and intermidiate shaft of ship propulsion system.

 

[MikeHalloran]

What ANSI suggests for a tolerance is not relevant; do not let the presence of a standard confuse you. A manufacturer specifies tolerances based on the requirements of the product... or at random, or on the advice of an astrologer.

Having done so by any means, they then have a commercial duty to meet their own requirements.

If you bought the parts from a third party, you're screwed.

If you bought the parts from the manufacturer who established the tolerances, and he thinks you're measuring wrong, he should damn well be out there measuring, himself.

Be sure to preserve the letters you got from the manufacturer; your lawyer may need them.







Mike Halloran
Pembroke Pines, FL, USA

 

[rob768]

Check with the associated classification society. They should be able to make sensible remarks on this subject.