I have a 11" x 29 " Weiss WBL290F Lathe that I purchased last month. There is a thumbing sound and you can feel the feed rod pulse. This happens with feed rod engaged at the quick change gear box and the carriage/ cross slide power feeds are not engaged. It is most noticeable with the carriage 10 inches or closer to the head stock. This thumping sound with feed rod occurs in either feed rod direction and either spindle direction forward of reverse. I can feel the feed rod pulsing at the end of the base. This goes away when I engage either the the carriage or cross slide power feeds. I'm thinking I have a slightly bent feed rod, but not sure if that is it. Any suggestions of cause?