Before I start you may ask why not send out the crank for a polishing. Two reasons. One, this is a budget project. Second I don’t think a crank shop will want to do a polish only. They will see the slight damage and wear and insist that the crank needs to be turned. Before I go that route I’ll try a clean up first. We’ll just have to see how it goes. I’ll tackle the main bearing journals first. I’ll then check clearances with standard or .001 service bearings. If I can’t get within spec ( .0005 to .0025) I may have to bite the bullet and send it out for grinding and polish and buy a set of under size bearings.
I’m going to try to freshen the crank using the old mechanic’s solution. I prefer sport laces as they have a wider flat surface to use over the sandpaper. I tried different combinations of paper and ended up using: 600,800,1000,2500 and fine crocus cloth. I used wet sandpaper, but I was having a problem getting it to spin nicely with the lace. I decided to try a little lubricant. I sprayed some WD40 on the wet sandpaper and tried that. It worked very well.
I used 600 grit for as long as it took to smooth out the journal surface. I used each strip only twice. I washed the used strip in water after the first use and discarded it after the second run. Once the journal was smooth I ran each of 800, 1000 & 2500 twice with water and WD40. The final run was with dry crocus cloth for the final polish.
This task is going to take awhile so my next post may not be for a bit.