Boring and sleeving bearing housings in a vertical milling machine
Editor's Note: The procedures outlined in this article exclude explosion proof motor end bracket rebuilding. Many motor service centers bore and sleeve end brackets (end bells) in machine lathes. When using a lathe you need one large enough to swing the outside diameter of the end bracket and the large mass is hard to indicate true. Many times it is difficult to clamp onto the lathe chuck or faceplate. When rotating a large mass there is always a chance of the part coming loose and causing damage to the end bracket or injury to the machine operator. We have bored and sleeved end brackets for more than 25 years in a vertical milling machine. We find the mill is a more useful machine; it is faster and more accurate to indicate in and set up. The boring of the diameters are true and concentric and it is much safer to rotate a cutting tool and not the part. Following is a step-by-step procedure to bore and sleeve end brackets in a vertical milling machine.