What is permissable defect (gauge) area in a precision bearing bore?

[bigj2]

I have a part with a 4 inch precision bearing bore that has a defect in the bore due to an insert breaking, and causing a small gauge in the diameter. This means my ABEC 7 outer bearing race will not make 100% contact with the bore that it is pressed into, this bearing has small balls because the shaft is around 3 inches on the od. This is a special spindle application and will the shaft will be rotating a few thousand RPM. Does anyone have a specification of how much actual contact is needed for the bearing to run properly and not fail prematurly? Are there any articles that discuss this subject?

 

[diskullman]

I assume you mean gouge or scrape on the surface of the housing bore. Have you repaired this scrape? You could always consult Loctite's engineering for instructions for their bearing retaining compound.

Russell Giuliano

 

[mfgenggear]

if you want to salvage

grind/turn bore oversize in the id, to leave .001 min plate per surface. leave a step adjacent to the shoulder (length will depend on radii at corner, usually .015 max length.)
since chrome has difficulty building up in corners.

QQ-C-320 engineering chrome plate .004 min per surface in bore.

grind id to bore size required.

it will last longer than the parent material.

Good Luck

 

[BobM3]

Tough question. It's not uncommon to machine a groove in the OD of the outer race to allow for a snap ring mounting option. Some bearings include holes in the outer race for introducing lubricants. So some lack of support for the outer race must be o.k. It's hard for me to believe that a small gouge or spiral groove in the bore would cause any problem.