Good advice above.
Looking down on your very last pix, from the underside of the mount,,, it looks like the drive roller is at a slight angle ! This would mean that the opposing mounting holes for the drive roller are NOT aligned. This could cause binding & would be a manufacturer's defect.
Looking down on your very last pix, from the underside of the mount,,, it looks like the drive roller is at a slight angle ! This would mean that the opposing mounting holes for the drive roller are NOT aligned. This could cause binding & would be a manufacturer's defect.