Hi Guys, a while back I posted about an issue I was having with finding vintage Timken tapper bearings for an early 1950`s Cooper petrol engine. The bearings were available if I was prepared to cough up $350 each plus delivery and taxes. Rather than dump this nice vintage engine I decided to modify the crank shaft and housings to accept modern metric size tapper bearings. A lot of searching on bearing manufacturers web sites and a lot of phone calls to my local bearing supplier and I found NTN 32210 bearings would be an adequate replacement.
The outer diameter of these bearings is about 1.5 mm larger than the original, while the internal diameter is about 10 mm larger than the crankshaft, the width of the bearing is about 2 mm less than the original, a big issue with adjusting the end float! The load rating and life expectancy of the 32210 is a little lower than the originals but since one of the originals was still serviceable after 60 plus years I will have to live another fifty years to wear them out, not very likely but I live in hope!
The two housings have been in the lathe and bored out to take the 90 mm cup, I have turned up two bushes to to enlarge the crank shaft from 1 9/16" to 50 mm, these have a 2 mm flange to allow for the difference in bearing width. This allowed me to cut gaskets to bring the end float back within tolerance.
I have posted some pictures, hope this will help someone in the same situation.
Bob