#SNAKESAFE JALBUM CRACKED#
Note the thin inner bridge of brass that has been cracked to remove the collar. This protects the bearing from being cut by the grinding wheel.
#SNAKESAFE JALBUM CRACK#
This can be cut off carefully with a small carborundum wheel mounted on a Dremel tool:Ĭutting the brass inner collar of the spur gear.Ĭut carefully through this brass ring until only a thin bridge of brass remains, then crack the bridgeīy inserting a screwdriver into the slot and twisting it. The toothed nylon gear should pull off easily, but this leaves the underlying brass collar that has been firmly pressed onto the eccentrically-mounted steel ball bearing. Once the left knob and washers are removed, the whole fine focus shaft and spur gear assembly should easily pull out from the right side: Left side of fine focus shaft with two small washers.
Then remove the left fine focus knob, being careful to retain in the proper order the two small washers beneath the knob: Then, using a specialized spanner inserted into the two small holes in the underlying cover (a lens wrench works well), unscrew the circular cover that forms the center of the larger coarse focus knob:Īfter the cover is removed, the spur gear is visible, with the crack appearing as a dark space in the white nylon gear: Thank you to Mark Morris who notes that the current batch price is $75.įirst, viewing the microscope from the back, remove the right fine focus knob by removing the single screw holding it onto the shaft. Do NOT lose any of the irreplaceable small parts! * Note added April 16th 2016 by the Micscape Editor. Replacing it turned out to beĪ relatively simple process, as described below. With $50 * and a few days’ patience, I had my gear.
Mark, the only North American source for these gears, works with a machinist who hand manufactures replacement Nikon S brass spur gears, and had two remaining from the last lot – probably a significant fraction of the world’s remaining supply. Nikon Model S with KT base, providing Köhler Illumination.Īfter a week of fruitless phone calls all over the United States, Bob Lair of ScopeDoc, a fellow member of the international Amateur Microscopy group, suggested that I contact an old associate, Mark Morris: However, the fine focus mechanism moved unevenly, revealing a broken fine focus gear and a potentially serious problem. Turning on…” This problem was fixed in 10 minutesīy re-soldering a flange on the bulb, and, apart from some dirt on the knobs and a few paint chips and dust, and, the instrument was in beautiful shape. It had not been used for 20 years and was advertised as “…not I purchased this Model S-Kt scope with lenses on eBay for $75. This problem is well known in microscopy circles. Hundreds of otherwise excellent Model S microscopes have been shelved or broken up for parts for no reason other than this one defect. Brass replacements for this gear couldīe purchased as aftermarket parts for a number of years, but are almost completely unavailable today. Since molded plastic materials were not as structurally sophisticated in the 1970s as they are today, with time this plastic ring contracted and broke, disabling the fine focus mechanism and causing thousands of service calls. This nylon gear, used probably because it never needed lubricating, was constructed as a 107-tooth nylon ring surrounding an inner brass collar pressed onto an eccentrically-mounted steel ball bearing on the fine focus shaft. However, this wonderful line of microscopes suffered from one serious design flaw, ironically resulting from one of the few plastic (nylon) parts on this otherwise superbly-crafted instrument: the infamous Nikon S fine focus spur gear. The image (shown right) is of my own, recently-restored Nikon S-Kt. Nikon designed these scopes with many interchangeable components so that a scope could be customized to every application…” The Nikon Ske and Nikon Skt, were research grade microscopes, and the Nikon Lke with constant Köhler illumination and changeable nosepiece was the top of the line in its day. “…the black Nikon S scopes that were first released in the 1960s … are still hallmarks of versatility and quality and have developed a faithful following despite their age. The Nikon Model S microscopes from the 1970s, with their quality all-metal construction, excellent craftsmanship and optics, shiny black finish, and multiplicity of options, are still some of the best general-purpose and research microscopes ever developed:
0 kommentar(er)
