05-10-13, 01:31 PM
The diameter I got when I checked them was is 0.123 inches or 3.12 mm, there is probably a standard dimension close to that because when I took them into a bicycle shop and asked if they had any bearing like it he looked up a chart and had them in stock. They were the same size as the bearing in the rear bicycle sprockets used with the derailers
Left hand drill bits are available in most good tool shops and maybe Halfords. Use a variable speed drill with a reverse action and do not run the drill to fast. Take you time and apply pressure but do not force it and finally keep it straight. I used a normal black and decker battery operated drill with a fully charged battery. The top bolt is the most difficult due to its close proximity to the cover, just don't push the bit all the way into the chuck to give clearance from the cover edge.
Left hand drill bits are available in most good tool shops and maybe Halfords. Use a variable speed drill with a reverse action and do not run the drill to fast. Take you time and apply pressure but do not force it and finally keep it straight. I used a normal black and decker battery operated drill with a fully charged battery. The top bolt is the most difficult due to its close proximity to the cover, just don't push the bit all the way into the chuck to give clearance from the cover edge.