Hi BB,
You have raised some interesting thoughts there mate. I spoke to our forum historian, CyberJack, yesterday about this issue and to try and work out the cause. He said that as an apprentice, he found that this problem was very prevalent on many Scott Bonnar Model 45 machines he worked on.
Here we have the dilemma, was the bearing surface designed to be a 'push fit' or a 'sliding fit'.
Grumpy has suggested it is actually what is called a 'transitional fit'.
Obviously this was a design issue at the factory, and the bearing area was made so as the bearings could be put on and removed from the shaft by hand....removing the need for a bearing puller; which can only grab the outer ring of the bearing, resulting in brinelling of the bearing surfaces. wink
The plot thickens....
cheers

Please do not PM me asking for support. Please post your questions in the appropriate forums, as the replies it may receive may help all members, not just the individual member.
Kindest Regards, Darryl grin