Fault analysis and solutions:
The length of the thread is incorrect. The reason is that the matching of the hanging wheel is incorrect or the position of the feed box handle is incorrect. You can recheck the position of the feed box handle or check the hanging wheel.
Partially incorrect The reason is that due to the local error of the screw thread of the lathe itself (generally caused by wear), the screw can be replaced or repaired locally.
The uneven pitch of the entire length of the thread is due to: o The axial movement of the screw. o Axial movement of the spindle. o The open and close nuts of the slide box and the lead screw are not in the same axis, resulting in poor engagement. o Sliding box dovetail guides are worn, which makes the opening and closing nuts unstable when closed. o The gap between the wheels is too large. Through the inspection: o If it is caused by the axial movement of the screw, the adjustment round nut at the connection between the screw and the feed box of the lathe can be adjusted to eliminate the axial clearance of the thrust ball bearing at the connection. o If it is caused by the axial movement of the spindle, adjust the spindle rear adjustment nut to eliminate the axial clearance of the rear thrust ball bearing. o If it is caused by poor engagement between the opening and closing nut of the slide box and the screw, the opening and closing nut can be trimmed and the opening and closing nut gap adjusted. o If the dovetail guide rail is worn, dovetail guide rails and inserts can be prepared to achieve the correct fit requirements. o If the hanger clearance is too large, readjust the hanger clearance.
The slub pattern of the turning parts is caused by the periodic error of the gear transmission from the main shaft to the screw. For example, the gears in the hanger box and the gears in the feed box are due to their own manufacturing errors or local wear. Or the eccentricity of the gear on the shaft causes the center of rotation to be low, resulting in uneven periodic rotation of the screw and periodic unevenness in driving the tool movement, resulting in the appearance of slub patterns, which can be replaced with errors or worn gears.