The Leinen LZ4SB leadscrew is supported by two bearings. One of them, the corresponding to the adjusting end, has been eroded maybe for a deficient lubrication. This need to be faced again to recover the bearing surface. We plan to do that using a boring head on the milling machine. To support the part in an orthogonal position first an adjusting stud is turned in a lathe. This will guide the bearing when clamped to the table.

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The two speed driver of the lathe runs in an oil bath. Two plugs let to replace the oil when needed. We made two operations with them: Adding a neodymium magnet to the draining plug to let it to catch the debris. The magnet is a counterbored ring bought at Aimangz. The magnet was screwed to the internal part of the plug. The plus are in a difficult position to be tightened.

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The lathe uses a flat belt to transmit power from the speed change to the spindle. After painting the stand it is now time to install the belt. The belt installed was a 42mm Esbelt LF-14 nylon-leather combined belt supplied by Armengol-Prat. This belt should be glued in-place. This was done by the supplier itself by using a hot gluing press as shown in this picture: After the waiting time to cure the belt glue the belt was tensioned to 0.

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Leinen lathe works face the arrival line. Now we painted the lathe stand and installed three anti-vibration rubber supports. Although it was an easy job the overall result was really impressive. Below there are some pictures showing the result. Note that the headstock is now screwed to the bed!

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In the last post I explained that, after filing the rear spindle oil reservoir a leak appeared. The leakage was big enough to empty the reservoir in some days. It needs to be repaired :-/. I waited to finish the lacquering of the lathe stand top. Now the headstock can be mounted again in the lathe ans it is easier to work on it: After that I unscrewed the casing of the rear bearing.

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There has been not many advances during last weeks, However, the lathe bed has been cleaned and prepared to be lacquered as show in the following pictures. We also worked on the lathe head, cleaning it and polishing the handles, After painting it again I replaced a couple of oil level screens and filled the spindle oil dwells. The result was that the back dwell has a mall oil leakage. It should be repaired.

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After mounting again the lathe apron we tested it and find a slight chatter when turning the hand wheel in one direction. Some time of careful inspection convinced us that the the source of the noise is one of the gears of the train. We didn’t check all the train gears before because to disassemble this section of the train we need a couple of special wrenches. Now it is mandatory to build them: a pin wrench socket for the shaft of the noisy gear and a special screwdriver to extract the rod that supports the switch mechanism.

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The apron Following with the overhauling of the Leinen LZ4SB now the star is the apron. The Leinen apron is double walled and all the mechanisms run in an oil bath. It has an clever mechanism to stop the transversal and the longitudinal advances when there is too much torque. This allows to work with adjustable stops during automatic turning or facing operations. Power transmission between the feed bar and the apron is done through a worm drive placed inside the apron case.

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