Trouble with sunray contact wheel

[DanGraves]

I bought 2 contact wheels from sunray. One is a 3 " that they sent when I ordered a 3 1/2" wheel. They sold me to keep it and sent another. I offered to send back but they said they would not need it back. I put it on my KMG grinder and have been using it for about 4 months. Today I took it off and here is what it did to the bolt. I spun the wheel holding with one finger on both sides with fingers on the bearing hole. I could feel that each bearing was out of line. I then preformed the same test with the 3 1/2" wheel and could feel one bearing was off but the other fine. On the 3 1/2" (never used) the bearing that had a slight out of round in the hole was tight and did not spin as free as the other bearing. I learned in My machine class course that if you press in a bearing with to small of hole (2 thou off) it can make the bearing tight. My question is "Has anyone else had similar problems?" Here is a picture of the bolt (came with the KMG).

 

[mike-E]

to me it looks like there was no pressure holding the bearings in place(no pre-load) and the wheel was just spinning on the bolt for some time. Do the wheels have spacers between the inner races? if you get a new bolt try to get a socket cap with more shoulder length. socket caps tend to be slightly bigger than hex heads, and typically stronger/harder too.

 

[DanGraves]

I think you are right Mike. There are no spacers. I think I can make a small washer to use to put a pre-load on the bearing without touching the rubber seal. Thanks.