Setting up a wood cutting bandsaw, there are thrust bearings which are set at 90 degrees to what I would expect. The blade is supposed to run on the diameter (face) rather than the circumference.
This seems illogical - the same set up on my metalwork bandsaw works with the thrust bearings running with the back edge of the blade just touching the circumference, which makes sense to me. But not the bearings on this other one.
Is there a good reason why it's designed like that?
By contacting the face rim of the blade support bearing at the edge (as these do when properly adjusted) the back of the blade is supported by a long flat section of metal (which will rotate, with some sliding, if properly adjusted) as opposed to a point contact with the curved outside of the bearing. A greater area of contact reduces the pressure on the blade over the contact area for a given applied force. However, as you have observed, different machine designers make different choices here. Both appear to work. These bearings should not contact the blade when not cutting, per most manufacturer advice.
TL;DR: It's been done this way for more than 50 years and it works, so there's no need to change it.
