I'm in the process of tearing down and cleaning a '69 Bridgeport and I found that the gibb on the Y axis has considerably more wear than the gibb on the X axis. It even has a power feed on the X axis and I would have thought that this one would get the most wear. However, the Y axis gibb shows a lot more wear and has even been shimmed. Is there such a thing as a thicker gibb I could use to get away from the shim?