05-06-2015, 12:17 PM
The easiest test is to check wear on the ways. Put the table and saddle in the middle of their travel range with binders off, and start tugging. Standing in front of the machine (operator position), push and pull on the handle by the feed box. Any significant play, negotiate downward on the price. If it's barely detectable, that's usually within the range of a simple gib adjustment.
A common problem with the variable speed heads is (especially with "genuine" Bridgeports) is the bushings for the variable speed drive. Bridgeport ones are unsupported on one end and being plastic, they tend to fail more often. The Taiwanese machines like that usually have a bearing on the bottom of the shaft to strengthen it and they last a lot longer. Simple to check under power by just running up & down through the speed range. If it sounds junky, it probably is. If it sounds smooth, buy it!
A common problem with the variable speed heads is (especially with "genuine" Bridgeports) is the bushings for the variable speed drive. Bridgeport ones are unsupported on one end and being plastic, they tend to fail more often. The Taiwanese machines like that usually have a bearing on the bottom of the shaft to strengthen it and they last a lot longer. Simple to check under power by just running up & down through the speed range. If it sounds junky, it probably is. If it sounds smooth, buy it!