One of the first issues I noticed after acquiring this lens was that the focusing ring was extremely stiff. At certain points, it required considerable force just to turn it. Considering that this is a 50-year-old lens, it's no surprise—the original helicoid grease inside the focusing mechanism has most likely dried out over the decades. Instead of providing smooth lubrication, it has become a source of resistance.
Following the previous article on rear-end disassembly, this installment covers the disassembly, cleaning, and re-lubrication of the focusing helicoid. The first step is to remove the entire optical assembly. Looking from the rear of the lens, once the aperture linkage, aperture ring, and related components have been removed, the retaining ring that secures the front optical assembly can be unscrewed. The complete optical unit—including the front lens group, aperture assembly, and rear lens group—can then be lifted out from the front of the lens, leaving only the focusing helicoid behind.
這顆鏡頭入手之後，令人困擾的問題之一是對焦環很緊，有些位置甚至需要非常用力才能轉過去，畢竟是50年的老鏡頭了，鏡筒內的潤滑油應該都乾掉了，原本潤滑的功能變成阻力。
接續上篇拆開後鏡筒之後，這次就來拆開對焦筒、清潔、重新潤滑。首先，要把整個鏡組取出，從後鏡筒觀察，光圈開閉連桿、光圈環等相關的零件拆除後，再將鏡頭前面的鏡組固定環卸下，即可將整個鏡組、光圈筒和後鏡組從前方取出，剩下的就是對焦筒了。
The retaining ring that secures the front optical assembly is the first ring adjacent to the lens barrel.
緊鄰鏡筒內的第一圈壓環就是用來固定整個鏡組
The focusing helicoid consists of three main components:
(A) The outer barrel, which supports the optical assembly and the aperture housing.
(B) The focusing ring, engraved with the focusing distance scale.
(C) The depth-of-field scale ring.
On the underside of Ring C, there are two metal tabs positioned 180 degrees apart. These tabs couple Ring C to Component A, and each tab is secured by two screws. After removing the four screws and lifting off the two metal tabs, Component A can be separated from the combined B + C assembly.
對焦筒由三個零件組成 (A) 固定鏡組和光圈筒的外筒 (B) 有對焦距離刻度的對焦環 (C) 有光圈景深刻度的環。C環的底部相對180度位置有兩個與A環連動的鐵片，每個鐵片有兩個螺絲固定，將這兩個鐵片卸下，即可將這Ａ環和B+C環分解。
Inside Ring B, you will find a set screw that secures the infinity focus position. After removing this screw, Ring B can be separated from Ring C. I first used WD-40 to dissolve and remove the hardened grease from the helicoid threads. Afterward, I cleaned away any remaining WD-40 with isopropyl alcohol. Once the threads were completely clean, I applied a thin, even layer of medium-damping helicoid grease before reassembling the three rings by reversing the disassembly steps. The focusing ring now turns exceptionally smoothly.
B環內部可以看到一顆無限遠刻度的固定螺絲，將這顆螺絲旋下，便可將B環和C環分解。我先使用WD-40清洗螺紋上已經乾掉的油脂，再用酒精將WD-40清除，最後在螺紋上一層中度組尼潤滑油，之後反向操作上述步驟便可將這三個環再組合起來，轉起來非常順手。
When threading Component A back into the combined B + C assembly, it is important to engage the helicoid at the correct starting position. After the two metal coupling tabs have been reinstalled, Component A should be able to travel all the way to the bottom of the B + C assembly, which corresponds to the infinity focus position. Finally, reinstall the optical assembly, the rear aperture control mechanism, the M42 mount, and the remaining components. With that, the restoration is complete.
當A環要重新旋入B+C環，須注意螺紋旋入的位置，當上述兩個鐵片固定後，A環需能夠到達B+C環的底部(也就是無窮遠的位置)。最後裝回鏡筒，以及後端的光圈控制機構相關零件、M42接環等，就大功告成了。
B環內部可以看到一顆無限遠刻度的固定螺絲，將這顆螺絲旋下，便可將B環和C環分解。我先使用WD-40清洗螺紋上已經乾掉的油脂，再用酒精將WD-40清除，最後在螺紋上一層中度組尼潤滑油，之後反向操作上述步驟便可將這三個環再組合起來，轉起來非常順手。
When threading Component A back into the combined B + C assembly, it is important to engage the helicoid at the correct starting position. After the two metal coupling tabs have been reinstalled, Component A should be able to travel all the way to the bottom of the B + C assembly, which corresponds to the infinity focus position. Finally, reinstall the optical assembly, the rear aperture control mechanism, the M42 mount, and the remaining components. With that, the restoration is complete.
當A環要重新旋入B+C環，須注意螺紋旋入的位置，當上述兩個鐵片固定後，A環需能夠到達B+C環的底部(也就是無窮遠的位置)。最後裝回鏡筒，以及後端的光圈控制機構相關零件、M42接環等，就大功告成了。
