So yesterday I went out to my shop to work on a project and started up my Porter Cable 334 ROS. It started up just fine and very quickly sounded like it was running in wet cement. I turned it off and note that the pad was hard to turn. I removed the pad and discovered that the bearing on the eccentric shaft was extremely stiff to rotate. I was able to remove the bearing without much difficulty other than the snap ring flew off the snap ring pliers and went flying and ricocheted off of a couple of things before it stopped. Fortunately I was able to find it after a very brief search of the floor.
The bearing was a NTN 6202/15 according to the labeling on the bearing. I called a local bearing supplier and they said they had the bearing in stock so I went to pick it up. Fortunately I took the old bearing with me and the man at the counter noted that the ID of my bearing was measuring 16 mm and the specifications for the new bearing said the ID was 15 mm. He was able to locate a different brand bearing with a 16 mm ID and identical thickness and OD. When I returned home and installed the new bearing it fit perfectly on the eccentric shaft. The shaft measured 15.8 mm so the 15 mm bearing would not have gone on. The sander worked perfectly with the new bearing.
The lesson here is that you should always take the old bearing with you when you are buying a new bearing.
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