Tid-Bit 22 - Of Oil, Oilers and Oil Sinks
Published in the January 2014 NAWCC Bulletin, starting on page 76.
It is not uncommon to find a question or two when I log into my e-mail each morning. This morning I read: “When I wind my Gustav Becker i have to put pressure the other way on the drum to get the clock to run. then it keeps good time. what is the answer needs oil?”
I get questions like this quite often – in fact, during the recent webinars on putting together a 3-weight Vienna Regulator mechanism this seemed to be the topic that generated the most intense interest.
When I first started working on watches and clocks I was in much the same quandary as the Becker owner. There are lots of oils offered by the various clock supply companies, all of which are “the answer” for a horologists needs. Initially I talked to others in my local chapter and heard lots of mixed reviews – and decided to try the oil that got, perhaps, less bad-press than the others.
Years went by, I bought out several collectors and ended up with quite an assortment of oils. During the same period I had the chance to see how oils performed in the clocks I was restoring. My observations can be generally lumped into three categories:
The oil turned green or brown.
The oil disappeared – or perhaps the mechanism was never oiled.
The oil thickened, or even solidified.
During the same period my “day job” included learning a bit about the production of lube oils, spending time in a Tribology lab (a lab run by the company I worked for that focused on developing new oils and evaluating their properties) and patenting improvements for a process used in making lube oils.
I can’t say I have extensive experience in the lube oil industry, but I have at least had a chance to work with those who did.
Perhaps 5 years ago I started going through mechanisms I had restored years earlier. Funny thing was that I continued to see pretty much the same issues that I had observed when working on mechanisms others had restored. Some pivots were dry, those not dry all had discolored oily residues, and some of those residues were pretty darned thick!
It was about 8 years ago that I also started using automotive motor oil on some of the larger pivots in Vienna Regulators. As time has gone by I have used it on ever smaller pivots until finally I started using it on all but the winding drums arbors, where I used Mobius mainspring grease.
Which, in a long winded way, brings me to two mechanisms I recently had a chance to go through a second time.
The first mechanism was from a floor-standing 3-weight Vienna Regulator. I restored it just over 5 years earlier and, when it sold, I went through it to make sure everything was copacetic.
As part of my inspection as I take apart a mechanism I look at the pivots under a 10 power microscope. Under magnification I could see a small meniscus of golden oil at the joint between the pivot and the shoulder on the arbor. Clear, golden fluid, looked just like the oil I had used on this mechanism. As I continued my inspection I noted that right around the pivot holes, in the bottom of the oil sinks, the brass was bright and shiny, while the brass farther away from the pivot holes was a little tarnished. Not bad, but not as shiny as the brass that had a bit of oil on it right by the pivot.
All of the pivots were in excellent shape, absolutely minimal impact from 5 years of operation, though the Moebius grease that I had used on the winding arbors had gone green.
The second mechanism came from a lovely little miniature Vienna Regulator that I had sold 5 years earlier. Most of its pivots were completely dry. As in when I rotated the pivots between my fingers they did not show any residual oil at all. The only exceptions were the winding arbor and the large pivot on the minute arbor – both of which I had lubricated with motor oil. They showed residual oil that was in great shape.
Whilst I have focused on two very specific mechanisms, my experience with them reflect, and pretty much summarizes what I have learned from working on perhaps 300 Vienna Regulator and a bunch of other mechanisms. To wit:
Burnished pivots stay burnished and exhibit minimal wear
Some Horological oils evaporate and leave no detectable residue
Some Hoorlolgical oils polymerize (change colors) and thicken
Quality synthetic motor oil works great
One has to wonder why someone with my background in lube-oil production would not switch to motor oil long before I did. In fact, I have asked myself that very question as I have inspected mechanisms I had worked on years before. The only conclusion I have been able to come up with was that I was concerned by the comments I had heard from other clock repair folks. Comments like:
“You need a very thin oil or the clock won’t run”.
“Motor oils have additives and must never be used in a clock”.
“Horological oils are special and won’t drain out of the oil sinks”.
None the less, years ago I started using motor oils in clock mechanisms. Granted, I started using motor oils in larger mechanisms, like British long-case and hall clock mechanisms, and still used Horological oils in finer mechanisms. Since that time, after seeing finer mechanisms gum up or dry out, I have been using motor oils in all of the clock mechanisms I work on. And have quit using Moebius main-spring grease in any application.
In retrospect I realized that I was somehow sequestering my “on the job” knowledge – not applying what I knew from the lube-oil world to the clock world. In part I suppose that was because I had talked to, and learned from so many horologists who each had their favorite Horological oil. In part because I was truly a newbie to the clock world and didn’t realize that perhaps the question of which oil to use demanded a more thorough review.
Which brings us to this article, in which I lay out my recommendations, based on my experiences working on mostly Vienna Regulators, and provide a bit of the rational I developed by applying the knowledge gleaned from my time as an engineer in the petroleum refining industry.
So, why is oil needed at all? I think the easiest answer is that presented by Wherner Stehr and Klaus Dobler in “Of Fried Sausages and Bearing Damage”. They observe that when lubricated bearings run dry the friction can increase 100 fold.
While the 100 fold increase is pretty dramatic, I know that the mechanisms I work on stop when the oil evaporates. Even if the pivots are perfectly burnished. If not properly burnished my experience teaches that long duration Vienna Mechanisms will not run even with appropriate oils.
Hydrodynamic Lubrication
Lubricating oils create a separating film between surfaces of adjacent moving parts to minimize direct contact between them. In clocks the oil is dragged by the rotating pivot to the load-bearing space between the pivot and the pivot hole. This is referred to as a “Hydrodynamic Lubrication”. Figure 1 is a simple depiction of such a bearing.
Read MoreIt is not uncommon to find a question or two when I log into my e-mail each morning. This morning I read: “When I wind my Gustav Becker i have to put pressure the other way on the drum to get the clock to run. then it keeps good time. what is the answer needs oil?”
I get questions like this quite often – in fact, during the recent webinars on putting together a 3-weight Vienna Regulator mechanism this seemed to be the topic that generated the most intense interest.
When I first started working on watches and clocks I was in much the same quandary as the Becker owner. There are lots of oils offered by the various clock supply companies, all of which are “the answer” for a horologists needs. Initially I talked to others in my local chapter and heard lots of mixed reviews – and decided to try the oil that got, perhaps, less bad-press than the others.
Years went by, I bought out several collectors and ended up with quite an assortment of oils. During the same period I had the chance to see how oils performed in the clocks I was restoring. My observations can be generally lumped into three categories:
The oil turned green or brown.
The oil disappeared – or perhaps the mechanism was never oiled.
The oil thickened, or even solidified.
During the same period my “day job” included learning a bit about the production of lube oils, spending time in a Tribology lab (a lab run by the company I worked for that focused on developing new oils and evaluating their properties) and patenting improvements for a process used in making lube oils.
I can’t say I have extensive experience in the lube oil industry, but I have at least had a chance to work with those who did.
Perhaps 5 years ago I started going through mechanisms I had restored years earlier. Funny thing was that I continued to see pretty much the same issues that I had observed when working on mechanisms others had restored. Some pivots were dry, those not dry all had discolored oily residues, and some of those residues were pretty darned thick!
It was about 8 years ago that I also started using automotive motor oil on some of the larger pivots in Vienna Regulators. As time has gone by I have used it on ever smaller pivots until finally I started using it on all but the winding drums arbors, where I used Mobius mainspring grease.
Which, in a long winded way, brings me to two mechanisms I recently had a chance to go through a second time.
The first mechanism was from a floor-standing 3-weight Vienna Regulator. I restored it just over 5 years earlier and, when it sold, I went through it to make sure everything was copacetic.
As part of my inspection as I take apart a mechanism I look at the pivots under a 10 power microscope. Under magnification I could see a small meniscus of golden oil at the joint between the pivot and the shoulder on the arbor. Clear, golden fluid, looked just like the oil I had used on this mechanism. As I continued my inspection I noted that right around the pivot holes, in the bottom of the oil sinks, the brass was bright and shiny, while the brass farther away from the pivot holes was a little tarnished. Not bad, but not as shiny as the brass that had a bit of oil on it right by the pivot.
All of the pivots were in excellent shape, absolutely minimal impact from 5 years of operation, though the Moebius grease that I had used on the winding arbors had gone green.
The second mechanism came from a lovely little miniature Vienna Regulator that I had sold 5 years earlier. Most of its pivots were completely dry. As in when I rotated the pivots between my fingers they did not show any residual oil at all. The only exceptions were the winding arbor and the large pivot on the minute arbor – both of which I had lubricated with motor oil. They showed residual oil that was in great shape.
Whilst I have focused on two very specific mechanisms, my experience with them reflect, and pretty much summarizes what I have learned from working on perhaps 300 Vienna Regulator and a bunch of other mechanisms. To wit:
Burnished pivots stay burnished and exhibit minimal wear
Some Horological oils evaporate and leave no detectable residue
Some Hoorlolgical oils polymerize (change colors) and thicken
Quality synthetic motor oil works great
One has to wonder why someone with my background in lube-oil production would not switch to motor oil long before I did. In fact, I have asked myself that very question as I have inspected mechanisms I had worked on years before. The only conclusion I have been able to come up with was that I was concerned by the comments I had heard from other clock repair folks. Comments like:
“You need a very thin oil or the clock won’t run”.
“Motor oils have additives and must never be used in a clock”.
“Horological oils are special and won’t drain out of the oil sinks”.
None the less, years ago I started using motor oils in clock mechanisms. Granted, I started using motor oils in larger mechanisms, like British long-case and hall clock mechanisms, and still used Horological oils in finer mechanisms. Since that time, after seeing finer mechanisms gum up or dry out, I have been using motor oils in all of the clock mechanisms I work on. And have quit using Moebius main-spring grease in any application.
In retrospect I realized that I was somehow sequestering my “on the job” knowledge – not applying what I knew from the lube-oil world to the clock world. In part I suppose that was because I had talked to, and learned from so many horologists who each had their favorite Horological oil. In part because I was truly a newbie to the clock world and didn’t realize that perhaps the question of which oil to use demanded a more thorough review.
Which brings us to this article, in which I lay out my recommendations, based on my experiences working on mostly Vienna Regulators, and provide a bit of the rational I developed by applying the knowledge gleaned from my time as an engineer in the petroleum refining industry.
So, why is oil needed at all? I think the easiest answer is that presented by Wherner Stehr and Klaus Dobler in “Of Fried Sausages and Bearing Damage”. They observe that when lubricated bearings run dry the friction can increase 100 fold.
While the 100 fold increase is pretty dramatic, I know that the mechanisms I work on stop when the oil evaporates. Even if the pivots are perfectly burnished. If not properly burnished my experience teaches that long duration Vienna Mechanisms will not run even with appropriate oils.
Hydrodynamic Lubrication
Lubricating oils create a separating film between surfaces of adjacent moving parts to minimize direct contact between them. In clocks the oil is dragged by the rotating pivot to the load-bearing space between the pivot and the pivot hole. This is referred to as a “Hydrodynamic Lubrication”. Figure 1 is a simple depiction of such a bearing.
