I am narrowing a 9" ford housing in my shop. I have borrowed a narrowing jig, and I have all the necessary equipment. I have never done this particular activity before but I won't let that stop me .The jig came with no instructions.
My question is, what is the tolerance for misalignment of the bearing bore in the housing end, both radial and axial. I looked all over the 'net and found nothing. (I know the tolerance isn't 0.00",so it must be something)

Also, I am working with a rear end housing with the old style big,(3.150" OD), bearings and the heavy axle tubes. (1/4" wall)
The size of the housing end requires the end of the axle tube to be counterbored to allow the housing end to be inserted. I guess this isn't a problem with the thinner wall thickness tubes.

Has anyone here had any experience with doing this. The od of the housing end is 2.665 and the ID of the tube is 2.55 or so. It is a seamed tube so it is out of round as well as not concentric with the alignment jig bar. I have a feeling that I am going to be hogging it out to fit with a die grinder to fit but I thought I'd ask here and see if anyone had another suggestion.

One rear end shop told me they cut the insert end off, and just buttweld the end back on when they narrow them. I guess he doesn't realize that is where the seal is supposed to seat. I'm glad I am not taking it there.

Thanks for reading this, Mikey