Polishing pinion journals

[RJ Squirrel]

Hi all happy 4th! I rigged this up today to prep my new pinion for good bearing fit, it was bigger than it needed to be on each end. I dont have a lathe so I used my drill press with a socket on a hex drive chucked into it for the small end and a scrap of aluminum with a machine screw and a nut for a pivot with a washer and some grease to make it spin easy for the big end. A roll of emery cloth from Ace hardware plumbing section was just right width. S It worked so good I thought I should share some pictures.

 

[ckessel]

Improvise, overcome, adapt. Great thinking you have there.

 

[1 Wild R/T]

Why would you reduce the diameter of the bearing journals? I've honed the ID of bearing cones to make "set-up" bearings but on final assembly you go back with a new set of bearings as you want a good secure press fit...

 

[Geoff 2]

What Wild said. What problem are you trying to 'fix'?

 

[dvw]

I also polish the shaft to allow the bearing to be installed with less press fit. It's a quick process. Makes setup far easier. Especially for the front pinion bearing by allowing much easier removal of the pinion itself. This idea came from Strange Engineering. Been doing it about 10 years. I've seen no ill effects.
Doug

 

[68-500]

I’ve often wondered why the big pinion bearing needs to be such a tight press fit? So many other applications of tapered roller bearings where they can be installed and removed by hand.

 

[RJ Squirrel]

My new pinion (unknown manufacturer) was .0025 oversize on large inner bearing and .0015 oversize on small outer bearing. I turned it down to a good snug slip on fit for the outer and .001 oversize for the press fit on the large inner. I think anything bigger than that just makes it more difficult than it needs to be, especially if you have a press fit on the outer bearing and need to take it apart.

 

[Geoff 2]

They have to be a tight fit because of the tremendous load on them.

 

[dvw]

My racecar is still running the same bearings it started out with 12 years and over 1000 passes ago. A few different R&P sets which were all polished. Runs mid 1.2x 60ft
Doug