Seeing Is Believing! Or To See or Not To See

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1 Technical Tidbits-No. 14 & W C by Stephen Nelson (WA) Seeing Is Believing! Or To See or Not To See Two experiences reminded me of how important it is to be able to clearly see what we are doing. The first occurred some time ago when a friend in Oklahoma City approached me to see if I was interested in buying his clock repair tools. He explained that his vision had deteriorated and that he couldn t see the small parts any longer. Today, I would work with him to find a way for him to see. But he had approached me before I discovered the tools I discuss in this article. So I bought him out and we lost an NAWCC member. The second experience was at a recent breakfast meeting with some clock friends. One of the men had an American mechanism that just didn t want to run something was amiss with the escapement. The restorer had spent some time working on it, but frankly he was puzzled. When it was my turn to look into the bowels of the mechanism, I donned my 2 binocular loupes and saw that there were signs that one of the pivots for the anchor had been moved, which likely accounted for the problem the mechanism was experiencing. There are two aspects to seeing what we are doing. The first is being able to see well enough to spot the problem. The second is getting our minds to actually see, or perhaps the better word is discern what the optics allow us to see. Although the repairman could see the plugged hole after I pointed it out, somehow it just didn t grab his attention. But when it was magnified, the plug was too obvious to ignore. I suppose work experience is the best teacher in learning to discern what is important (or, in my case, luck), but I firmly believe that being able to clearly see the tiny bits we work on is the critical first step. And that is the subject of this Tech Tidbit the optics I use to see what I am working on. I use microscopes and binocular loupes when I work on clocks for another reason. I am not getting any younger, nor are my eyes. Optics can obviate the otherwise seemingly insurmountable challenges we all face now or will face in the future as our eyes lose their youthful resiliency. I have had students (experienced clock repair folks and customers who want to learn how to repair the finer weight-driven clocks) spend a half hour working on a pivot while using an Optivisor to see what they are doing. When I then look at the pivot under a microscope, I find they have not even begun to properly restore the pivot because they could not see what they were doing. As you read this Tech Tidbit, you may conclude that I emphasize optics too much and that some of the options I present are too expensive. I understand, but if you will understand that my fascination is working on Viennese pieces many that run for more than a week and some for more than a year and all with pivots that are very small and that have to be perfect. To do this work, I have to be able to see the quality of my work. I find that 10 optics are necessary to do what I do. Methodology used a Sony DSC-T200 8 megapixel digital camera I in closeup mode with no flash to shoot pictures of a pinion and pivot through the various optical devices discussed in this article. Every effort was made to position the camera to reflect the distance from the eye to the optical device. Likewise, the optical devices were positioned so that they were at the appropriate distance (focal length) from the pivot and pinion. The pictures shown below were all shot with the same camera lens settings and were all cropped identically to give reasonable representations of the relative size of the image seen with each optical device. Reading Glasses When I turned 50, I discovered the joys of reading glasses. Simply put, reading glasses allow you to focus on objects that are too close for aged eyes to see clearly. Reading glasses come in various focal lengths. When you buy reading glasses, you will see numbers ranging from 1 to around 3: the diopter of the lenses. The diopter is the reciprocal of the focal length, measured in meters. In other words, the older you get, the higher the diopter you will need to see something close to your face as your eyes continue to lose the ability to focus on near objects. NAWCC Watch & Clock Bulletin May/June

2 TECHNICAL TIDBITS NO. 14 At one time I thought that diopter was the same as magnification. It isn t. The magnification of a pair of reading glasses can be calculated as follows: Magnification = (Diopter divided by 4) plus 1. Figure 3. Using a 10 jeweler s loupe. The following table will make this clear. Table 1 Magnification for Typical Reading Glasses Diopters Diopter Magnification While I am sometimes tempted, in the interest of expediency, to use my reading glasses as safety glasses I really do know better and have bought bifocal safety glasses specifically for working with my larger lathes and for work with woodworking power tools. I pretty much always have a pair of reading glasses with me and always have them on when at the bench unless I want to see something small. Then I either pull down a microscope or don a pair of binocular loupes. Jeweler s Loupe (singular) My mentor taught me to do watchwork using a jeweler s loupe. Under his tutelage I could do pivot work that made him proud. It is possible to do excellent work with a 3 or 4 loupe in one eye, though it truly is an art form that is mastered with patience and practice getting used to working with your eye very close to the piece you are working on. A 3.5 jeweler s loupe has a focal length of around 3.5 inches; a 10 loupe has a focal length of only three quarters of an inch: it is easy for your nose to get in the way at that point or get tangled up with a large chuck on a jeweler s lathe. Figure 1, above. Using a 3.5 jeweler s loupe. Figure 2. Pinion and pivot viewed through a 3.5 jeweler s loupe. Figure 4. Pinion and pivot viewed through a 10 jeweler s loupe. I have done some extremely good work with jeweler s loupes and have had the sore neck to prove it. Another option that is very similar to the jeweler s loupes shown in Figures 2 and 4 are the clip-on jeweler s loupes that mount on the temples of a pair of glasses. While I tend to knock them off of my glasses when I use them, they are a very effective and low-cost option for getting great magnification. If you look through two of them at once (they often come as a pair, as shown in Figure 5), the magnification significantly increases the product of multiplying the magnification of each individual lens. Figure 5. Clip-on jeweler s loupes. Optivisors Optivisors are a popular and inexpensive option for seeing things. It is not unusual for a student to show up at my shop with an Optivisor. Because I want to train people to use the tools they will use in their own shop, I have my students use their Optivisor for the first part of their time with me. Typically, they find that they cannot do the work I expect of them with their Optivisors. 298 May/June 2012 NAWCC Watch & Clock Bulletin

3 TECHNICAL TIDBITS NO. 14 Figure 6. Using an Optivisor. Figure 7. Pinion and pivot viewed through a No. 4 (2 ) Optivisor. Like reading glasses, Optivisors are most effective for doing general. They let you sit back from the workpiece and improve your closeup vision. They also offer better eye protection than reading glasses if something is thrown at your face; they are inexpensive, flip up out of the way when not needed, and are comfortable. Some have a flip-down eyepiece to give higher magnification. Nonetheless, I pretty much always have a pair of reading glasses with me and only keep my Optivisor because it used to belong to my dad, who did lathework on 12-inch pieces of drill pipe. Microscopes One day a car buddy called to tell me about a used microscope in a junk shop back in Oklahoma City that was special because it was mounted on an articulated arm! This made it extremely handy for viewing things on a clockmaker s workbench (Figure 8) In addition to giving excellent optics (as in really clear vision), these scopes allow you to see items nine inches away from the end of the scope, rather than having to be within three quarters of an inch of what you are working on, as is necessary with a 10 loupe. Because the microscopes are binocular, they also give you depth perception you can tell if something is farther away or closer to the scope. A second advantage of the setup shown in Figure 8 is that I can readily move the microscope up high enough that it is totally out of my way, which makes it very easy to have on hand but not in the way. When doing, it is very easy to pull a scope down, look at whatever needs looked at, and then push it back up and out of the way. The really big advantage is that microscopes make it very easy to see very small things. Rather than having to spend time getting used to using a 10 loupe, a scope instantly exposes the fine details, which in my world make the difference between a good and a bad repair job. In the words of a Canadian clock repairman: Used the scope today on a fly pivot. Again, what looked alright for an English longcase pivot with the naked eye and not too bad with the 4 loupe looked pretty poor with the scope. Went at it with yet finer files and then burnished. Even though the metal is softer than any in better clocks there was a marked improvement. The scope just got addictive. Figure 9. Using a microscope. Figure 10. Pinion and pivot viewed through a 10 microscope. Figure 8. Microscope set up with a 10mm Levin lathe. I find 10 to be optimal for my work with scopes, though the eyepieces can be replaced to give 6, 15, or 20. It is interesting that the distance from the end of the scope varies by only about three quarters of an inch when switching to different eyepieces. In addition to jeweler s loupes and microscopes, there are several other options discussed below. NAWCC Watch & Clock Bulletin May/June

4 TECHNICAL TIDBITS NO. 14 Binocular Loupes first learned of binocular loupes when I visited my I clock customer/dentist in Oklahoma City. He had a pair of Zeiss binocular loupes that he used to inspect teeth. As time went by, I managed to find a pair for myself a wonderfully old pair that is smaller than the current style. Figure 11. Modern (top) and vintage (bottom) binocular loupes. Although these do not give the magnification of a microscope, they do provide excellent magnification and great depth perception when assembling a mechanism or perhaps inspecting as a mechanism comes apart. my pair on for hours while working in the shop; they are light enough that you don t notice them and small enough you can easily look around them. Typically, the earlier loupes are 2 just the right magnification to see very clearly the details of how a mechanism comes apart or goes together. Unlike the simple jeweler s loupe, the binocular loupe also lets you get your head up away from the workpiece into a much more relaxed position. They also give you depth perception, which allows you to more accurately place your hand, tweezers, or screwdriver as you work. The best option available today is the new, larger Zeiss binocular loupes, shown above. Although larger than the early loupes, they are very functional, provide exceptional clarity, and are typically 2.3, so they have a bit more magnification than the smaller, earlier ones. A comparison of the magnification of the 2 binocular loupes discussed in this Tech TidBit and the 2 Optivisor (Figure 7) shows that the binocular loupes produce an image that is roughly 50 percent larger than the Optivisor. This is a function of the focal length of the two devices; the binocular loupes have a shorter focal length, making the pinion/pivot appear larger because they are closer to the eye. I have included a couple of shots of other loupes that are readily available on ebay. These all give acceptable magnification, but some are really quite heavy when worn. They can be purchased for a lot less money than the Zeiss loupes, and many are mounted to a pair of glasses so you can have lenses fitted that match your glasses prescription. Figure 12. Using binocular loupes. Figure 14. Alternate binocular loupes designs. It is also possible to buy binocular loupes that are virtually miniature microscopes mounted to a headband. Figure 15. Using Heine 3.5 headband binocular loupes. Figure 13. Pinion and pivot viewed through 2 binocular loupes. I am quite partial to the binocular loupes produced in the early half of the twentieth century. These loupes are much smaller and lighter than the later styles, but they offer equally excellent optics. I often find that I have left Figure 16. Pinion and pivot viewed through Heine 3.5 headband binocular loupes. 300 May/June 2012 NAWCC Watch & Clock Bulletin

5 You will probably notice that the magnification in Figure 16 is very similar to the magnification in Figure 13 with the Zeiss 2 loupes. Note that the Heine loupes shown in Figure 16 have a much greater focal length around 17 inches from the end of the lenses; with the greater viewing distance the greater power is required to achieve the same apparent magnification. I find these very handy when working on a larger mechanism, especially if the large mechanism is in a large case. TECHNICAL TIDBITS NO. 14 Figure 17. Using Zeiss 5 headband binocular loupes. Figure 19. Used colposcopes on ebay. You can perhaps see that the arms are a lot shorter than on the scopes I prefer. Between the shorter arms and reduced arm flexure these scopes cannot be as readily lifted up out of the way. But they do provide excellent vision! Boom Microscopes Another option is a microscope mounted on boom arms. These are even less flexible than the colposcopes, but they are also a lot less expensive. Some, like the one below, are set up so that the head can rotate out of the way when not needed. Figure 18. Pinion and pivot viewed through Zeiss 5 headband binocular loupes. I also have a Zeiss 5 headband binocular loupe with good working focal length, great depth perception, and very pricey. Colposcopes The microscope I use was developed for ophthalmic surgery in the mid-1900s. With their long articulated arms they allow a great deal of flexibility at the bench or on a lathe. But they are fairly rare. A viable alternate is the used colposcopes, which are readily available. Colposcopes are used for gynecological examinations. Many of the colposcopes I see on ebay have excellent fiber-optic lights, and some even use zoom microscope heads that provide anywhere from 5 to 40 magnification. Another interesting feature of colposcopes is the way their articulated arms are set up; when you move the microscope head from side to side, it stays focused on the same point. This is sometimes quite helpful (when you want to see the other side of an object), but usually not so much, because you likely want to look at another part of the mechanism. Here are pictures of a couple of colposcopes I recently saw on ebay. Figure 20. Boom microscope on ebay. Magnifying Lamps number of clock repair folks use magnifying lamps A when putting mechanisms together. I think they can be very effective for assembly work, provided you don t need to see small details; the one I used for this article has about the same magnification as a 2 Optivisor too little magnification for doing pivot work but not bad for putting the levers on the front of a mechanism. NAWCC Watch & Clock Bulletin May/June

6 TECHNICAL TIDBITS NO. 14 Figure 21. Using a magnifying lamp. Figure 24. Pivot and pinion viewed through a 10 power microscope. Figure 22. Pinion and pivot viewed through a magnifying lamp. Digital Microscopes new option that at first glance looks very attractive is A the small digital microscopes that are now available. If you have a computer in your shop and if the computer is new enough to handle the scope s processing speed requirements, this might be a good option for you. I have been experimenting with one, a Dino-Lite AD413TL, an extended working distance digital microscope. (Note: Dino-Lite s normal working distance scopes have to be positioned so close to the workpiece that I find them unusable.) You can see the microscope head just above and slightly to the right of my hand. You also can see the picture the scope produced on the computer in the background (actually, I had to cut and paste the picture onto the computer screen because I could not get Figure 23. Using a Dino-Lite digital microscope. a good picture of the pivot/pinion/burnisher when I was shooting the above shot). As you can see, it is possible to get great magnification. But the microscope s ability to provide fine detail and to handle glare from metallic components is marginal. Here are shots of the same pivot/pinion shot with my 10 bench scope and the digital microscope: Figure 25. Same pivot and pinion as shown in Figure 24 but viewed through a 20 digital microscope. I have tried stoning and burnishing a pivot under the digital microscope and find it does not offer the resolution or glare control to be an effective option. Granted, this is only a 1.3 megapixel microscope (Dino-Lite now offers a 5 megapixel option), but I suspect even if the above picture had twice the pixels in both the X and Y directions, it would still be much less usable than what I see through a 10 microscope. Dino-Lite had offered a digital microscope with a polarizing filter, but apparently there were problems with it, and the company pulled it off the market. If they can resolve the issues with the filter and significantly increase the pixel count, these may well become viable instruments. But the hassle of having to have a computer monitor on or beside your bench does not, in my opinion, make these a flexible option. The table on the facing page provides a summary of the optical devices discussed in this article. For additional information on the techniques Steve Nelson uses in his workshop, visit com/technicalinformation. Steve s is: steve@snclocks.com. 302 May/June 2012 NAWCC Watch & Clock Bulletin

7 Table 2 Optical Device Characteristics Optical Device Reading glasses Jeweler s loupe 3.5x Jeweler s loupe 10x Clip-on jeweler s loupes Focal length inches From end of device Varies with diopter From eye Depth perception Clarity Magnification power Low - 1 to 1.5 generally Cost TECHNICAL TIDBITS NO. 14 Benchwork Pivot work on lathe Best use Low Good Poor General 3 4 Nil 3.5 Low Good Good Closeup and lathework Nil 10 Low Difficult Difficult, but excellent Same range of options as the jeweler s loupes; also offers option of stacking loupes to increase magnification Very close and lathework Effective as jeweler s loupes in Figures 2 and 4, mount to glasses Optivisor Low Good Poor General Optivisor Low Good Poor General Optivisor Low Good Poor Closeup, simple jeweler s lathework Microscopes , 10, 15, 20, 40 Binocular loupe 2x Heine binocular headband 3.5x loupes Zeiss binocular headband 5x loupes Magnifying lamp Dino-Lite microscope extended working distance models High Moderate for really small parts High Too long a focal length Good to Too long a focal length All detail and inspection work. Some mounting systems are more flexible than others General and larger lathework Working on large mechanisms in large cases High Closeup and lathework Good 2 Moderate From 1 inch at 40x to 3.5 inches at 5x Nil Poor 5x to 40x power. See note. High Good Poor General Very poor, minimal depth of focus Marginal Low-resolution photography Note: The Dino-Lite folks have a novel way to figure their magnification. They include the size of the monitor in their figuring. Their numbers are roughly two times what would be more conventionally calculated. But if you are viewing their output on a 60-inch monitor, you could achieve much higher magnifictation. NAWCC Watch & Clock Bulletin May/June