Hello All,
I bet this satisfies LJ's thirst for a new topic and discussion.
I think there might be interest in the Smiths Chonometric cleaning, service and repair I am underataking. I have done a fairly extensive web search and have found almost no photos (I think I found a total of 1) of the inside of a chronometric speedometer. If I am correct, with the addition of my photos, our forum will become a major source of photos for others who are looking.
Removing the bezel was the first challenge. One site said to put on a leather glove and twist off the bezel by hand. If no-go, apply thin oil. I let Liquid Wrench sit overnight and still had no luck by hand. Thus, you see my approach using two strap-wrenches, which did work.
The speedo was in much better condition than I hoped. The lubricant was sticky. I washed it out with ether starter fluid after wrapping the odometer and trip wheels in plastic food warp to avoid getting too much solvent action on the numbers, which are said to be quite sensitive to any solvent. In retrospect, I probabaly should have removed the clockworks from the frame to wash it out, but no harm was done. By the way, the speedometer truly is a clockworks, as it is designed to update speed readout every 3/4ths of a second. Recommended lubricants ranged from instrument oil to motor oil. I chose Marvel Mystery Oil as being something in-between and which I believe to be a high-quality thin motor lubricant; this I applied with a baby's medicine syringe.
After lubrication (and quickly to avoid oil overspray from acting like a solvent), I cleaned the the odometer and trip wheels with cotton-tipped swabs and soapy water; no solvents allowed.
The one thing that was broken was the tripmeter reset shaft. Reset shafts for magnetic replicas are available, but I could not find one for this old clock, and I didn't want to wait just to find out that I can't get one. (If someone knows where I could find one, please let me know). I fumbled around my tool box and came up with an awl that was just 0.025mm larger in diameter than the 3mm original shaft, so I have fashioned a new shaft from that, as seen in the photos. The little toothed wheel and shoulder behind it are both from the original part. removed by drilling, and now swaged onto the new shaft. The tapered arm (not custom made) seen extending out from the trip shaft lifts the pawl during the rewind process.
There will be more photos and talk as I move forward, so, for now, that's it. Some of the photos are pre-cleanup and some are after. If you can't tell which is which and need to know, let me know. Also, I'm not being very disciminating with the photos, so they will be in multiple posts and in no particular order.
Richard
