I watched Mr. Marshman strip a Wollensak Betax No 5 lens and shutter down to its bare aperture blades clean it and reassemble it with no issues whatsoever. Its functioning a hundred percent better than before. The best part was that wasn't even what I asked him to fix! I had brought my Century 8x10 to him because I was having issues with the film back keeping tension and holding modern sheetfilm holders correctly.